Most likely a problem with the lift cable mechanism. There is a fairly recent post here with some really good diagrams of how the lift system operates. Considering how far out of whack it sounds, I would suspect that a pulley has broken or an entire lift mechanism has pulled away from the frame at a corner. This doesn't sound like a simple "adjust the cable" kind of thing.
Getting at and inspecting the components is a bit of work. They are generally hidden behind panels inside cabinets. At least one of them is buried inside your wet bath. Totally doable if you are fairly handy, but if not, I would be seeking a good RV repair shop to help out.
Depending on vintage and ownership, remember that Jayco offered a lifetime warranty on the lift mechanism for many years. Might be worth taking it to a Jayco dealer for possible warranty coverage.
And BTW - welcome to JOF!
ETA: Found the thread. Check out the 2nd post by @Sneezer here
https://www.jaycoowners.com/forums/f...tem-50323.html for the link to a repair manual from an Australian site. Similar or the same as the US Jayco mechanism.