Whats with matchmaking?

I just want to practice adc in norms, but in about 7/10 games im facing plats+ (i am silver) who just stomp me then taunt and bm. Is it time to just play ranked to practice shit then get flamed when i underperform? Or do i keep getting rolled by higher ranks and watch them spam their mastery rank (wonderful idea btw riot) while im stuck in fountain. <-- Literally my last game