Quality of animation mostly depends on time, the availability of animators and the skill of said animators, One Piece is doing amazingly right now because it has a ton of talent working on it, because of the connections of the current arc's director and Toei being a favourable work place, though regardless if a studio has those qualities or not staff shortage is inevitable for many shows because there is way too much anime being made for the number of animators that exist, this is why many upcoming or amateur animators from overseas have received chances to work on anime.
Whatever Pokemon is doing right now is probably the best it can, they can't do battles more often because the standards for action animation has changed (AG and DP had a ton of battles sure but outside of Iwane and Tamagawa episodes almost all of them had next to no actual animation) and they can't magically summon more skilled animators regardless if they had the money to hire them or not if they're already busy with other projects, people like Maenami and Tu Yong Ce who did impressive stuff early in Journeys are now regulars on One Piece for example, but Maenami at least returned for a bit in the current OP and Sirfetch'd VS Gallade so I have hope that we'll see them when it truly counts near the end, and the Iris episode proved that we don't need to rely on Iwane for key episodes, and stuff like the Grookey walk shows that new talent is still being cultivated at OLM. Animation is a rocky road especially in today's anime industry, we still have it pretty good relative to many other properties (OLM doesn't seem to be overworking people to death for one, though the hours are surely still insane relative to the pay) and most of the shortcomings are much more understandable than most comments on these forums would lead you to believe lol. Have sympathy for the artists.
