I've managed to install Ubuntu 22.04 on my mac Air 9,1 (late 2020), works most of it, and unlike Apple made it look, it's possible to have dual boot without any hack.
First, you need to fully disable secure boot, you can do it holding command + R to enter your UEFI settings, and disable all secure boot functions.
Just boot into Ubuntu T2 Live ISO, first try all it out, if most of things works, there's guides for those who don't.
When ready, go to install Ubuntu (use a new SSD please) and go next, when asked how do you want to install, select other, locate your SSD UNIT, and make a partition to ExT4 mounting to /.
When selecting the UEFI partition, just select the internal NVME, I don't know if it's Ubuntu or Apple or both, but it's smart enough to create a separate folder for ubuntu (in my case) but still have it's Apple folder.
I know you already messed up a little, but when you recover, you can do this step by step and easly install it.
Well, first kudos for people at https://t2linux.org, they did an amazing job. Mine's working very well, use my answer as you own risk, but I'm here to help. Wish you luck on your journey my friend :)