2013 Ford Expedition 5.4 - Random stall while driving progressed to crank-no-start, no useful codes?

My 2013 Ford Expedition 5.4L originally started with a random stalling problem while driving. It would shut off unexpectedly, I’d have to pull over, turn the key fully off, and then it would usually restart and run fine again for a while. Over time the stalls became more frequent, but it would still usually restart.

Then while it was at a mechanic, it reached its first true crank-no-start condition. No repair work was actually done there because the issue was too inconsistent and there was nothing reliable to catch while it was at the shop, so I ended up picking it back up. Since then it has progressively gotten worse. It rarely starts now, and the last few times it did, it ran rough, sputtered, and died. There are no useful codes unless something is unplugged during testing. I’ve already replaced the OEM crank sensor, both OEM cam sensors, OEM FPDM, and relays, plus done fuse/relay testing. Looking for direction before I keep throwing parts at it.