I've had plantar fasciatis for about 15 years but after help from a physio I've been able to be free of it most of the time.
First of all, I would say - definitely don't walk around barefoot!
I personally find wearing heels of a certain height makes a huge difference, including for slippers. One of the worst periods of pain I ever had was a few years ago after I had been wearing flattish slippers with a memory foam padding on the sole for a few months.
I have orthotic foot supports which I wear with lightish shoes such as sandals which don't give much support at the sides. However, especially in winter when I am wearing boots most of the time I don't need the supports.
It was physio which got me sorted out and I still do the exercises I was shown if the pain starts flaring up I find they make a huge difference fairly quickly.
If it wasn't for the pandemic, I would really recommend going to a physio, but if you don't want to go just now, you could try some exercises on your own. Obviously, check with GP if you have any health issues which could mean that these exercises are risky for you. Here are some exercises similar to the ones I find helpful: www.versusarthritis.org/media/3094/plantar-fasciitis-exercise-sheet.pdf
The exercises I do involve standing (with shoes on) with my hands holding on to the mantelpiece and one foot with heel on floor and toes on hearth, then I lean back a bit, holding on to the mantelpiece and not moving my foot, till I feel my calf muscle stretching. I do this with each leg 10 times (even if only one foot is giving me problems). I also do the same sort of exercises lying on my back on my bed - I have one leg at right angles to bed, loop a towel folded lengthwise over my foot and hold on to towel at each end, then pull down on the towel while keeping my leg at right angles. I try to do 10 times for each leg and repeat a couple of times daily for a few days.) If the plantar fascitis is bad, the calf muscle will feel really tight, but after a few times doing the exercises, my calf muscle is more relaxed and the pain in my foot improves. I find even one round of exercises can make a difference.
If it is really bad, freezing a plastic tumbler of water, wrapping it in a towel, then massaging the arch of your foot with it can also help.
Good luck!