How to get better at league?

I've been playing for about 7 months now. I really want to become a better player in general, but I'm honestly too scared to play anything other than support (which I'm kind of good at I guess). I want to try different champions and roles but always end up getting flamed. I sometimes try to explain that I'm still somewhat new to this game, but I eventually end up getting 4 reports anyway. Moreover, I never got a single piece of advice from these people. Nobody ever explained what I could have done better. It's always like, 'n00b ur lvl 30 shut up stupid btch reported'. TLDR: I suck at this game. Is there any way I can become a better player in general? I'm too scared to try anything new, but I don't feel like playing support forever. I'd appreciate any kind of tips/websites/different streamer suggestions etc. Thank you in advance!
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