I feel like it’s important also to acknowledge that while, yes, Mrs. Bennet pushing Mr. Collins on Elizabeth is completely understandable from a material point of view, it’s also setting up a repeat of the Bennet’s marriage that Mr. Bennet absolutely does not want for any of his daughters. Not just because Elizabeth would be unhappy, but because she’d be unhappy for the same reasons Mr. Bennet is unhappy with Mrs. Bennet.
Mr. Collins is repeatedly shown to be essentially the masculine equivalent of Mrs. Bennet: obsequious, social climbing, and utterly incapable of conducting himself in society without embarrassing himself and anyone connected to him. Charlotte is only able to handle the situation by either a) manipulating him so as to avoid him as much as possible or b) maintaining a stone cold poker face at all times:
When Mr. Collins said anything of which his wife might reasonably be ashamed, which certainly was not seldom, she involuntarily turned her eye on Charlotte. Once or twice she could discern a faint blush; but in general Charlotte wisely did not hear.
This is an objectively shitty situation for Charlotte to be in, but it’s one she went into voluntarily, as the benefits (namely independence in running the house and having space of her own) outweigh the detriments for her. Lizzy would not be doing it voluntarily.
Sure, Mrs. Bennet’s primary concern is making sure her daughters are not in poverty, but Mr. Bennet’s is making sure they’re not trapped in unhappy marriages for the rest of their lives. In both Jane and Lizzy’s cases, he is only happy when he believes that they’re choosing husbands of good character and compatible personality, and extremely upset if he thinks they’re not. Compare his initial reaction to Bingley’s proposal (which comes after spending significant time with him, during which he confirms his good character and disposition) with Darcy’s (which doesn’t):
Bingley was punctual to his appointment; and he and Mr. Bennet spent the morning together, as had been agreed on. The latter was much more agreeable than his companion expected. There was nothing of presumption or folly in Bingley that could provoke his ridicule, or disgust him into silence; and he was more communicative, and less eccentric, than the other had ever seen him. […]
He then shut the door, and, coming up to her, claimed the good wishes and affection of a sister. Elizabeth honestly and heartily expressed her delight in the prospect of their relationship. They shook hands with great cordiality; and then, till her sister came down, she had to listen to all he had to say of his own happiness, and of Jane’s perfections; and in spite of his being a lover, Elizabeth really believed all his expectations of felicity to be rationally founded, because they had for basis the excellent understanding and super-excellent disposition of Jane, and a general similarity of feeling and taste between her and himself.
[…] Mrs. Bennet could not give her consent, or speak her approbation in terms warm enough to satisfy her feelings, though she talked to Bingley of nothing else, for half an hour; and when Mr. Bennet joined them at supper, his voice and manner plainly showed how really happy he was.
Not a word, however, passed his lips in allusion to it, till their visitor took his leave for the night; but as soon as he was gone, he turned to his daughter and said,—
“Jane, I congratulate you. You will be a very happy woman.”
Jane went to him instantly, kissed him, and thanked him for his goodness.
“You are a good girl,” he replied, “and I have great pleasure in thinking you will be so happily settled. I have not a doubt of your doing very well together. Your tempers are by no means unlike. You are each of you so complying, that nothing will ever be resolved on; so easy, that every servant will cheat you; and so generous, that you will always exceed your income.”
Her father was walking about the room, looking grave and anxious. “Lizzy,” said he, “what are you doing? Are you out of your senses to be accepting this man? Have not you always hated him?”
How earnestly did she then wish that her former opinions had been more reasonable, her expressions more moderate! It would have spared her from explanations and professions which it was exceedingly awkward to give; but they were now necessary, and she assured him, with some confusion, of her attachment to Mr. Darcy.
“Or, in other words, you are determined to have him. He is rich, to be sure, and you may have more fine clothes and fine carriages than Jane. But will they make you happy?”
“Have you any other objection,” said Elizabeth, “than your belief of my indifference?”
“None at all. We all know him to be a proud, unpleasant sort of man; but this would be nothing if you really liked him.”
“I do, I do like him,” she replied, with tears in her eyes; “I love him. Indeed he has no improper pride. He is perfectly amiable. You do not know what he really is; then pray do not pain me by speaking of him in such terms.”
“Lizzy,” said her father, “I have given him my consent. He is the kind of man, indeed, to whom I should never dare refuse anything, which he condescended to ask. I now give it to you, if you are resolved on having him. But let me advise you to think better of it. I know your disposition, Lizzy. I know that you could be neither happy nor respectable, unless you truly esteemed your husband, unless you looked up to him as a superior. Your lively talents would place you in the greatest danger in an unequal marriage. You could scarcely escape discredit and misery. My child, let me not have the grief of seeing you unable to respect your partner in life. You know not what you are about.”
Elizabeth, still more affected, was earnest and solemn in her reply; and, at length, by repeated assurances that Mr. Darcy was really the object of her choice, by explaining the gradual change which her estimation of him had undergone, relating her absolute certainty that his affection was not the work of a day, but had stood the test of many months’ suspense, and enumerating with energy all his good qualities, she did conquer her father’s incredulity, and reconcile him to the match.
“Well, my dear,” said he, when she ceased speaking, “I have no more to say. If this be the case, he deserves you. I could not have parted with you, my Lizzy, to anyone less worthy.”
Mr. Bennet clearly isn’t going to forbid Lizzy from marrying for money rather than love – this is what he initially thinks is going on, and he gives consent to both Mr. Darcy and Lizzy anyway – but he really, REALLY doesn’t want her to. He KNOWS what happens if you jump into a bad marriage for the wrong reasons, and he is going to try to talk her out of it by any means possible. He has to be convinced that her attraction isn’t a passing crush or a coldblooded bid for Darcy’s wealth, but something real and capable of being maintained over time, and ONLY THEN is he truly okay with it.
Like, Mrs. Bennet’s concerns are understandable and rational given her situation and that of the family, but so too are Mr. Bennet’s given his own situation.