I don’t know if it is feasible to make playtesting available independently of connection to Epic’s servers, like in Unreal Engine proper, were you can play your map anytime.
Reason being is that probably 1 times out of 20 the connection can’t be established and playtesting fails. Oftentimes you might not need full connection, just checking some detail in the level, like a collision or whatever detail you are working on, that needs a quick check in game.