That's how league Is supposed to be played. There's a reason we have 2 week patch cycles, its to make an arms race as players try and test and adapt. Instead most folks just obey Tier lists, streamers, and pro play like its a walkthrough to victory with out accounting for their own skill on champions or if the strat they are copy pasting requires higher level of teamplay then what their MMR typically employs. So we end up with 1 tricking's probably the best way to win consistently if you can find the champ your good with but it has its issues and ends up sucking fun out of the game if you enjoy playing ranked, you get grossly undreskilled on other champions that you cant play as well as your 1 trick. Probably the healthiest way for long term enjoyment is to have a decent pool of mains in every class you really enjoy playing so you can be viable in a large # of metas and adjust to the times as needed or when ever your burnt out on playing 1 champion.
Disclaimer, some folks really enjoy being dedicated to 1 champion only and hey that's also fine because they enjoy it. I personally observed with friends that otp just for wins they burned out and lost interest a lot faster then my homies with a good pool of champions. Where as the homies I have that play lots of stuff and don't obey tier lists are still online and playing lol every week. The guys who will 5 man with me and do shit like 5 support comps remain the guys who only wanted to climb climb climb and failed to get unstuck when they capped at their skill have almost all quit, and several got pissed at me when they asked for help and I pointed their mistakes and they are not in elo hell they just need to improve. (don't ulti into a team of 5 as sion when your teammates are takeing barron, its not a 1 v 9 your the one fking up man, yes you landed all your abilitys and CCd the enemy mid and adc... alone. with no on near you, as your team focused an obj that mattered. DUDE that's on you not teammates. 1 game later, Dude... don't 1 v 5 as Leona....)