It almost sounds like what I had with my Stealth. I'd bleed the hydraulic system, let it sit for a couple days, & then I could shift into all of the gears again with the engine running.
A couple more days later it would lock me out again, I'd let it sit for a while, & could eventually be able to get into a couple gears with the engine running before getting completely locked out.
I finally bit the bullet & dug deeper into the transaxle (figured it was a physical clutch malfunction from the start, but kept taking people's advice & did the easier things first)...Turns out one of the spring perches on the sprung disc had broken off & was affecting the disengagement every time it fell into the wrong spot (it was an OEM Exedy clutch assembly & the P.O. had receipts showing it was replaced ~12k miles ago)).
I'm not too sure how often that happens with the OEM discs on these cars, but perhaps that could be your issue, too.