One Plus is the newer exclusion in the list of reducing number of new devices in the US which can run Custom ROMs. Right now, I only really know of the Pixel and the Nothing line of mobiles which can run Custom ROMs.
Americans, what are our options?
Just don’t get xiaomi if you’re in the US. I used to have one when I moved from India last year and majority of the bands were unsupported, so I was stuck on 2G-3G speeds.