Conversely I don't have a problem with early gennin Sakura's behaviour and personality, in fact I think that it could've been incredibly realistic if it was portrayed as a self preservation mechanism that stems from the bullying she faced.
It's not unusual for people who have been bullied or outcasted because they have something 'wrong' with them (a cruel concept that is often enforced despite being bullshit) beginning to obsessively fixate on fitting in. Going out of their way to be liked and act like everyone else serves as a self defense mechanism to avoid it happening again in the future, often coupled with insecurity and supressing - sometimes even forgetting- your actual personality. Especially if it happens at a younger/formative age.
Seeing/hearing how other girls her age supposedly begin to care about their looks, watching their mass infatuation with Sasuke, how everyone treats Naruto harshly, and so on. Except these behaviours get magnified or exaggerated out of proportion because hey look at me! Acting completely normal and like other people I'm fitting in no problem!!!! Even inner being a result of squashing down her actual personality to fit in with what other people as a whole find palatable - not just Sasuke.
The anxiety and insecurity could even subconsciously be effecting her performance as a shinobi. Don't give it your all (unless Sasuke-kun is watching, I need to impress him) other people might think you're weird for caring so much, don't try so hard (unless its a competition with Ino) or people will think you're cringe, subconsciously self sabotage without realising it (because otherwise I'll get made fun of for being smart because studying and enjoying reading is for losers and I'll get called a nerd and be isolated again unless I act delicate and helpless like the heroines in those romance novels I have to blend in seamle-)
It'd also add another layer of importance to her breakthrough in the Forest of Death. The departure from who she used to be and the true beginning of her evolution yes, the vow to change and catch up to her teammates yes, but also a realisation and a promise not to hold herself back or sabotage herself for the sake of others again. Sakura has cut herself loose from who she once was. She will bloom from a bud to a flower. The boys will watch her back this time. And her old bullies and anyone who might laugh can eat fucking dirt - she isn't going to lose herself or hide away ever again.