It's hard to advise over a screen sometimes, but I think leaving them alone can be the best, sometimes. But, to contradict, sometimes you need to move them...They're brainless... Hard to say. The mouth open like yours is, concerns me, but on the other hand, the ruffled edges looks good. IMO, ruffled edges trumps open mouth, in goodness... Yours has good ruffles...
I think blasting one with light, that can't handle it, CAN cause irreversible damage. On the flip side, not providing one with enough light causes the algae to die off. Find what it can handle before deflate, and dial it back slightly. It's easier to bring one back from bleaching, rather than trying to acclimate one that's been damaged by blasting, that refuses to reinflate. I've lost enough this way to see, even though some of the most experienced guys promote light blasting out of the gate, I disagree with them on this.
What ever it takes, to keep them inflated 100% of the time. #1 goal. Not 100% size, but 100% of the time full, not floppy. Floppy usually means big trouble. Open mouth not as dire, but still a concern. ALL of mine have hidden mouths, as in, covered in tentacles. Can't see unless tents flop out of the way from flow, and even then sometimes the mouth is still hidden. It will take months for them to get to this point, most likely. Sometimes lack of light can help keep them stay full, but only in the beginning during acclimation. Ultimately, they need light blasting, (and that's the end goal), but blasting in the beginning I've killed more than I care to share...Double digits, and I'm not talking teens or twenty's.... Some will respond well to light blast, but most won't. IMO, the biggest cause for deflation or inability to attach.
It may help, if you take a picture of it the same time every day, and compare yourself. Make sure it's going forward, not backwards. Maybe a pic at best and worse and compare. Posting pics here may help someone else see something you miss too.
Best of luck to you with this guy, I really think this one can make it.

Sorry to pepper your thread with info you may not want or need, thoughts just keep coming out, in hopes to help someone that reads...