With that tight of a budget I wouldn’t hold your breath.
Something like coreboot is incredibly niche for someone to care about. Newer device like above will be costly because of economies of scale. And for something on a hobbyist level to take off it would need to be at least a few years old + the right person getting the bug up their ass to make it work (well).
I had a W540 until the end of 2021 and besides it crashing from a hardware issue it was plenty fast for me at the time. As long as you’re not doing too intensive work it’s probably plenty as long as you’ve got the full power 45 watt quad core i7s.