>>52752443In that case you absolutely want to make it Glalie, but it's not worth it either way if you don't unlock Mega Glalie first. It won't even do enough damage to seriously consider for raids otherwise.
For PVP, just remember that for Master League you want full IVs when possible (just like raids) and for Great/Ultra League you usually want low attack and high stats otherwise. But if you're not even planning to try PVP don't bother keeping those. If you do plan to try pvp, use the site pvpoke in order to see if a Pokémon is suited for any given league.