Via Vermaden:

https://failsafe.monster/posts/fbsd-t480/

Same for the T580. The last good ThinkPads:

Last dual/removable batteries.

Last SSD bay, supporting SATA and NVMe without ripping the mounting bolt off of the motherboard.

Reportedly support 64GB RAM.

Optional “best” track pad.

Supports many operating systems. (sub toot)