The most supported seems to be lineage, but support is slimmer than you think. Lineage is still quite clunky At least in my area. Out of 15 phones I looked at in the local store not one (except a pixel) was actually supported by lineage, similar models, or models with an extra letter. I tested out a couple Motorolas but they weren't supported, nor have drivers and boot images available to flash aosp. FP isn't available in the US.