I'm gonna link a post I made in the metagame discussion thread where I mention our beautiful apple boye a bit. Appletun is really good at stall. It competes with Ferrothorn as stall's cover girl grass type, but has some unique niches due to its rather large resume of quad resists, a few regular 50% resistances, and a quad weakness turned regular weakness to boot thanks to thick fat. They share roles as fat leech seeders with Appletun being more successful as an anti-water because of its quad resist which is relevant with Dracovish and Gyarados all over the place right now in addition to having more reliable recovery than Ferrothorn with Recover as well, but Ferrothorn has the benefit of role compression as a hazard setter. Appletun also has a lot better HP than Ferrothorn, but sacrifices the stellar defensive stats that Ferro has. (not that base 80 defenses flat is terrible)
You can read a bit more about Appletun in Stall
here. I mention the niche provided by Apple Acid, but unfortunately I think my opinion has changed slightly with de-boosting being significantly weaker than boosting in the current metagame. The set-up Pokemon that are thriving right now are just too good at boosting multiple stats at once which makes Apple Acid an ineffective countermeasure. We would really appreciate the ability to trap since then Apple Acid can wear down fatter walls; but atm, it's pretty easy to just switch out and grass is already a type that does very not good offensively.
I was honestly really sold on this Pokemon when I saw it just because its so
DAMN C U T E, but I was afraid its stats and lack of a movepool was going to make it suffer in the pits of NU; but, once Dynamax is dealt with and we're not stuck in the offense hell that plagues the ladder right now, I'm honestly convinced Appletun isn't the rotten apple that a lot of people say it is and that it has potential ripe for the picking.