PVE mode to practice a Champ. (possible mastery rank 8+)

I think the current mastery system needs some change. When its up you can farm s+ easily and get your mastery lvl 7 in no time. This requires low skill and dosent prove that you are good at the champion at all. In addition to that if you are at low elo it is also way easier to get mastery level than diamond+ because down in low elo everyone sucks at the game and the skill level is really diffrent from game to game. One game you could get into a game with someone who just got out of placements the first time they really played the game and another game you could be matched with someone who has played the game for years.

I think we need a change to the mastery system as we know it. I think if riot introduced a PVE mode where you fight 1 or more AI's in a singleplayer battle that would prove how good you are with the champion, now there is ofcourse alot of diffrent aspects to this and it would be hard to make a specific fight for each champion to prove your skill level but i think it would be a fun thing you could do to practice your level with your champion.

A good example would be the oddesy event we had last year. Fighting kayn on the hardest difficulity was hard for some but for some it was easy. It needs to be a challenge getting mastery 7 not just something you get by farming trolls in a normal game.

I want to hear feedback on this cause i think it would be a very possitive thing for league right now.

EDIT: Didnt know they removed getting mastery from featured game modes