May be a little unpopular, but I don't really think that's possible or a good direction to go. We've pretty much got three different game modes:

• Competitive, with voice communication, the same group of people on each team every time, and markedly different common strategies (eg lane swaps just about every game)
• High-elo soloq, people generally know what to do, but without the same level of coordination
• Low-elo soloq, where there tend to be more off-meta picks and even less coordination

And each of these games has particular champions that thrive there but not in the others. Think of a champion like Kat, someone that abuses bad picking and low coordination and often did well and whose winrates dropped as you went up the tiers.

Then we have champions like Nunu that see competitive play sometimes but are middle of the pack for soloq (currently #23/46, per champion.gg). Or someone like Elise that was in nearly every competitive game but is bottom of the barrel (#40/46) in high-elo soloq.

That's not to say it's impossible to make someone decent in soloq and competitive, but competitive revolves around objectives primarily and being able to utilize flex picks and coordination. Making someone decent in Soloq, on the other hand, involves being able to perform well even without good coordination and have some tolerance for mistakes. In other words, someone that is good in both modes is someone that is good at controlling objectives as well as being able to carry the game without much coordination or knowledge of your teammates. And if they can do that much with so little, they're probably OP once you give them the coordination, communication, and strategy you have in competitive.