Ilia likes to lean heavy on his lead leg, this is part of how he pivots and quick steps in to position so efficiently. Balancing himself on his lead leg allows for very precise and fine foot movements that is all important for winning space and opening angles.
A nice oblique kick would very harshly punish him for such an unorthodox MMA stance. Once he's been scared away from balancing himself like that, his movements will become much more hampered and predictable, and his ability to win positional battles limited. If he doesn't shy away from his lead leg dominant stance, he will be at risk of getting finished from the oblique kicks.
The Max fight also proved that a kicking offense is extremely potent against Topuria. None of max's kicks did much damage sure, but they slowed Topuria down and stalled his strategy, which was a serious problem for him in that fight. Constantly presenting the right side body kick and the right side head kick keeps Topuria's all important right hand occupied and limits his ability to launch counters. It denies him the smooth pocket exchanges he wants and keeps the fight at an ugly kicking range. And you could see that the grinding pace the fight was going at was really starting to get to Topuria before he had that last burst of offense in the third. If Max hadn't essentially conceded the center of the cage from the jump, and had been a bit more creative in setting up offense from his kicks, that could have become a much different fight.
With all that said, I can't see Charles making use of these fundamentally important tactics to approaching Topuria. He's just not much of a kicker. I don't think he's thrown an oblique kick once his whole career