To share my experience, I had the Pixel Fold and I called up M1 to ask whether Pixel Fold is supported, I was told by M1 customer service Pixel Fold is not a supported device on their list.
I went ahead to add in M1 esim, it works and I just brushed off what I was told by M1 about my device not being supported. Come the day I was supposed to sell my Pixel Fold, I could not delete the esim regardless of all methods I could find online. In the end, I was advised by the phone shop taking in my device to do a factory reset. I was worried if I did not delete the esim before I factory reset the device, I won't be able to use the esim on my new phone. But no choice, I initiated factory reset and the phone prompted me to delete the esim, thankfully managed to delete the esim before handing over my phone.
So I would suggest to be careful about adding esim and decided not to use esim anymore.