>>52894077Red IS the strongest trainer in the games he appear.
Let's use Cynthia as a example since she actually has a nice team and is strong as fuck in the games she appear. When a player faces Cynthia she is, at base, a champion.i.e: pokemons in levels between 60-70. Sometimes lower. If we would put levels to trainer it's clear that Cynthia is champion level.
Red at base, in the games he appears, is above champion level. Pick the strongest trainer in those games and he will be 15+ levels above it. Base Red facing champion Cynthia has a higher chance to win just by level difference.
The Cynthia that fans claim is above Red is a non-canon version that you will face after 2 rematches. This version of Cynthia is not canon since her next appearance (BW) she is not even close to that level. (not to mention that red rematch team in stadium is stronger than hers).
Overall the best trainer in actual canon is red. Since he can train his pokemon to a higher level.
Cynthia can be considered to have a better team that is held up because she, in canon, never trained them like Red.