Improving without flame

So I m a sorta insecure person and it really annoys me that you can't really improve in LoL (mechanically you will improve automatically over time but I mean strategically). Every time I try a new build that might not be meta just to see whether it works for me I get flame flame flame. I'm unranked lvl 34 and I don't get it. It's normal draft, where else would I try these things? Bot games are not an option you might see 'hey I deal a lot of damage with this build' but there's no strategy... Queueing with higher elo players usually gets you even more flame because they want you to be as good as them (how?) and lower level players tend to blame everything on others.

Example: I recently played with a friend's friend who is Platin rank and he made fun of me for using a build which had worked for me before (against people of my level) and which I later saw a LoL streamer on Twitch use in the same position who is Master rank.

These things always demotivate me, I wish there was a safe space to play to imrove and not be talked down all the time. Help? Advice? [slayer-jinx-catface]