Nobody is working on suspend explicitly, but there have been some power management improvements lately that will also matter for suspend, for instance https://source.puri.sm/Librem5/linux-next/-/merge_requests/279
Personally I believe that it’s way more important to keep extending runtime battery life and treat suspend as the very last thing in the chain of things needed to be done for good power management. Suspend isn’t a magical answer to all battery life problems - if you need to suspend to get reasonable battery life you’re going to be very limited with what you can do with your phone.