Not a tropical fish but a brackish crab

My female red claw crab has been getting kinda opaque and slowed down eating a bunch, im assuming shes molting now because i woke up this morning and shes on her back, probably not intentionally i think she fell from her stick when she started molting. But i flipped her over super gently just in case so shes doesnt fail at molting but shes back on her back again. Its been probably 5 hours now and im a bit worried because it says it should take about a day but the actual molt should only be a few minutes.
ive had her for like 9 months, shes in a 20 gallon brackish water tank with land area and all that good stuff. The water parameters are probably as close to perfect as possible right now shes been really healthy and active since about a week after i got her all the way til now.
So to sum up my crab is taking a while to molt and im worried shes gonna fail what can i do to make it easier for her.

the water looks cloudy and the crab looks dead.

test the water and do a big water change and gravel clean the substrate.

I had both fiddler and red claw crabs (not at the same time) many years ago, red claw were more fun to watch but were real escape artist. None of mine lasted as longer as 9 months but back then we did not have all the info on how to raise them like now. I did have several molt. Sorry about your crab if he died.

Same thing happened to me the crab died later that week.