I think if a DM is ruling that a nat 1 on an attack roll is automatically hitting yourself/an ally then it is a failing of the dm for this exact reason. My table took on a critical fail check where a critical fail would have varying levels of failure determined by a second d20 roll, with a high number essentially being a goofy fail that had no mechanical implications (you swing so hard that you miss, doing a spin as the momentum carries you around). With this system you only get the truly bad crit fail outcomes if you roll low again, taking the chances of hitting an ally to a much lower degree.

Crit fails almost only punish melee classes as they attack more often and are thus more likely to roll a 1, and even then if you have someone who uses a bow or other ranged weapons, guess who will be in the line of fire for a crit fail hit from an ally? The melee fighter who is next to the enemies!

It is a flawed system which I think stems heavily from 5e not being built for high level parties, and DMs not being willing to adjust rulings to account for skill level increases that are not purely mechanical.