I have Galarian Slowpoke and a copy of both Pokemon Sword and Pokemon Violet, is there a way to evolve it without the DLC of either game?
According to Bulbapedia, the only ways to obtain a Galarica Cuff or Galarica Wreath in either SwSh or SV require owning the DLC and going to the respective DLC locations to obtain the item.
However, this does not prevent someone with the DLC from trading you a Pokemon holding that item, allowing you to obtain the item for yourself and use it in whatever way you like.
Hope this helps!
The only way to evolve a slowpoke in sw&sh or s&v without the dlc Is for someone with the DLC To trade you the required item. Otherwise, it is not possible to evolve it without the DLC.