Something about Roland dying makes it not that significant.
It's totally understandable that Marinette, Gina, Tom and Sabine feel sad about the death of one of their family members, but the viewer most likely will only feel sad because they experienced that loss/ they see their grandparent in Roland.
But other than that I don't care much about him dying
We saw him three~ times, I remember Bakeryx, Dearest Family and Simple Man (which was absolute hot, steamy and liquid shit)
His introduction is him either not talking to his family for decades because of racism towards Sabine, or if you wanna take the metaphor literally, over using rice flour instead of wheat flour (at least in the Italian dub idk if it changes in other dubs) in which he comes off as fucking insane, I can expect racism, but over FLOUR???
This man had no good reason to cut off his family and go live talking with rats like Cinderella and he gets away with it scot free. And from an outsider point of view, he is one of the worst characters in MLB morally (don't get me started on how Astruc tried to make us hate on Chloé claiming she is racist and then trying to make us feel sympathetic for basically the CEO of racism), and the show just forgives him because Marinette's bread is just as good as his. (Using Chat Noir as the judge, who as far as we know, doesn't have any culinary knowledge other than Camembert because of Plagg).
Again, it makes sense for Marinette to mourn him, that's her grandfather and she fought hard to have him in her life (even if he didn't deserve it).
But for viewers it's just another background character, at most a tertiary character, we only care because he represents OUR grandparents since he is the protagonist's