As the difficulty of Raids increases, the minimum level to participate also increases, in the first Raid the required level is at least 50, then it went to 60. What I want to recommend is that Leave the minimum level at lvl 50 and the game itself leaves the level of the pokemons at the recommended level for the Boss, as is the case in pvp, so we wouldn't need to keep leveling the pokemons in each Raid