https://www.thegamer.com/pokemon-legends-z-a-evolve-galarian-slowpoke-some-unusual-pokemon-side-mission-walkthrough/
In Pokemon Legends: Z-A, here is how to evolve Galarian Slowpoke into Slowbro & Slowking by getting its evolution items from a certain side mission.
how to getgalarian slowpokepokemon legendsevolve