I'm remembering the DS era where we had a proper spectator mode that flashed basic into on screen. Like "Charizard Fire/Flying" and "Mold Breaker: Ignores abilities" or "Tailwind 3-5 turns remaining"
Some well fleshed out version of that could solve the main issue here I think.

Actually, fighting games often avoid this problem by being able to highlight big moments on their own, supers being a prime example.
I don't know anything about League but if they have similar 'Big Impressive Moments' that can convey info about the impact of a decision, that might be a factor.

I just keep thinking about side-targeted Roar Farigiraf into Incineroar. Which is a sentence that needs explaining BEFORE I can explain why that play is amazing. The audience in the venue and the chat were hollering about it, but without them it wouldn't look like anything at all.

Types, type match-ups, abilities and how they interact, moves and their effects and where or who they target.
YouTubers like Wolfe's, False Swipe Gaming, and even Pokemon's official channel have tried to make this information accessible but all it does is bring people inside the bubble, not pop it.

The problem is in information. Following any FGC match can be as easy as watching a Dragonball Z fight, both sides are gonna hit each other until one wins, flashing lights and colors will be involved.
But with Pokemon, to appreciate a match on a basic level, you need to know so much more raw info.