New COH2 meta 101
Step 1: unequip the commander you want to pick from its original (!!) faction.
Step 2: click on faction icon to get the 5 faction menu
Step 3: RMB on the commander you unequipped at step 1. DON'T (!!) click on Equip yet.
Step 4: click on faction you want to use the commander on
Step 5: Press equip.
You can equip as many commanders as you want, just be sure to empty your whole loadout from the step 4 commander if you want more than 1 "custom" commander. If you have 3 vanilla commanders picked, the new commander will always go in the 1st slot.
Also, if you want to play Ally and Axis faction together in 2v2/3v3/4v4. Overload your internet by opening 4-5 720p YT vids in your browser, then count down to 1 with your AT and at 1, you click on start and the teammate switches factions. If you (the host) lags hard enough, LELIC servers will let u pick axis/ally :).
unfixable btw ROFL