We bought a house with a super cool original clawfoot tub that someone had attempted to DIY with an epoxy reglaze that was failing, and looked like you might catch something from it - it was awful. We went with a professional tub refinisher in our area, and are happy enough with the results.
There's a super professional version where you send it off to have it re-enameled but that's for serious preservationists and costs thousands plus shipping. The standard one for plebs and people who can's remove their tubs is essentially a paint job - which is what we got. They sand it down, fill cracks or dings and then several coats of paint later plus a topcoat you're good to go. It has a warranty, but you are forever restricted to the cleaning products you can use, and I imagine it will fail at some point. On top of that, it isn't perfect, and I notice every imperfection and dimple. However, its the only practical way of keeping a historic piece and it totally suffices to for the purpose. I'm just super...detail oriented. Ours is in our guest bathroom also, so it will last longer due to minimal use.
Its been a year and still looks good, with 50% use. Warrantied for 6 years, paid 165 to strip the old stuff and 465 for the refinish.
PM me if you want pictures.