Is being nice is a bad thing

I just read one of the post which also talks about the same question that I couldn't find the answer to it . Me (23M) had dated some women and what they would say is that I am "husband material ,green flag ,bf material" these things. But what I can seee is that being nice and genuine is a bad thing
So this girl which I dated she told me she had a rough past and her ex was toxic and all me being me was nice to her and kind of cared her being there for her but later at some point I figured out she lost interest in me and she used as "aid tape "just to heal her and after that she is healed she is not longer interested in me and find someone else So I thought maybe she's is the one who don't deserve me And after sometime I dated another one but after the deeds and she suddenly says I am way too good for her she don't deserve me I deserve better and better to stay away

I feel so stupid and see low Girls Is a guy being nice and genuine is too bad for you or I feel like I am attracting too much red flag girl Or should I buy my green flag character and be a red flag Because of all these things I kindoff lost the hope in love

And to the people "when the right time comes u will find her " stop saying this I lost my trust in love