I have taken 3 barefoot, not necessarily because they had problems (in 2 cases they did - 1 in the foot and 1 injured suspensory; one did not have any physical issues at all) and not permanently.
I had them working at BD and one at BS too, without shoes, as well as hacking 3 X a week.
I start with a couple of weeks for the foot to simply relax, no trimming other than any ragged edges. Then start with 100yds in hand on the roads, barefoot. If you have to boot to get them comfortable onto the road then do, but they should be OK on the actual tarmac.
I then increase by 100m whenever I feel it is right. Not every day.
As soon as they are road walking, I start to wave a rasp at them. Just to tidy up. It seems to become apparent what work needs doing as soon as you start to road walk.
I would keep road walking in-hand until you are doing 40 minutes or so comfortably. After that, I would maybe do a shorter ride under saddle. I found riding them really affected them when they are not yet strong in their feet, they can really feel it. Sometimes I would do part of the outing under saddle but with boots, then dismount, pull the boots and lead home.
The one that was bang sound (the mare I have just sold) but had shoes removed because I was busy with mum's illness, she was the one who never needed boots at all. Probably because everything was already working 100%. She simply increased her work, and after 4 months was even sound on hard core car parks when she was out competing. When mum took a turn for the worse, she went to a friend's where to get anywhere there was a 100yd hard core track, and she was fine.
The other two looked fabulous, but took longer to feel OK on uneven ground. They were the ones who had boots for car parks and for part of the ride. They took 6 months to do longer tarmac rides, and one was never 100% comfortable on hard core. I think it is because he already had foot issues. I didn't MRI, we nerve blocked to the source and gave a steroid injection in there as the vet thought that would likely be the treatment whatever the MRI showed. He had been lame before I owned him, but after a long rest was OK, but after I got him and took him eventing, the slight 'offness' came back. Hence steroid, barefoot rehab, return to more limited workload, never evented again. Not that he wasn't sound to, just that I thought if he did, he would not stay sound. For his benefit, I decided he was semi retired.
I had them on very clean beds, did a Cleantrax soak, bought some pea gravel for the drive so the soles had some abrasion every day, turned out on an arena that had large chunks of rubber too. All 3 were over winter, so not too much grass when they were out, plus no rock hard uneven ground. All 3 came off any hard feed, bar a little chop for the foot supplement from Progressive Earth, or in the mare's case she was rock hard so had Formula 4 feet as a hand treat.
Personally I would prefer to know what is wrong, but if you take it slow, the horse is having a form of rehab anyway. I would avoid the circles where she isn't sound altogether and only do stuff where she is bang sound. I did photo the feet and video the flight every month.
Good luck!