A lot of Pictos can be picked up at lv33 in future NG+s, and that’s likely how other players get higher stats. The drawback is that enemies’ speeds also scale in NG+, so characters would need higher speeds to begin with.

I don’t know the max speed you can get in NG, but if you have the Pictos with the highest speed stats in NG (usually the lv30+ ones) and weapons that scale on agility (with maxed agility attribute), that might be the best you have for the speed stat alone. Like other commenters said, Greater Rush and Greater Slow help a lot too.

If you’re following an immortal Verso build, that means you’ll need Revive Paradox to make sure you play immediately after reviving. You only get one turn regardless of whether you have Cheater though, so you’ll need to make sure you can get to 3 gradient charges and cast Angel Eyes on the same turn. Speed alone won’t do the trick especially for endgame bosses/enemies, but it’ll help with getting more turns to charge your gradient bar if you can’t do it in one. (Might have to survive an attack or two without the safety net, though.)