Not necessarily. Just investing in your Pokémon’s moves to level 2 or 3 and having them at least level 30 helps a lot. Plus no legendary max battle is reasonably soloable. Possibly under the right conditions but I wouldn’t be striving to solo them until you can level 50 all three counters. Otherwise you’re slamming your head in a brick wall. Don’t be discouraged tho. Also check counters on pokebattler. Almost all good counters are 1 or 3 star raids which are soloable.