The jacuzzi tub the house came with is big, grey, and (according to a scan of the manual I found) able to pre-fill via a phone call to its land-line modem* – if only land lines still existed. Mechanically though it’s fully sound and there’s no reason to replace it. Doing so would be a major expense even before factoring in the chaos it would create – one wall of the bathroom would need to come out, at a minimum. Much better for now to just freshen up the appearance.
A big part of the objectionable appearance was that the brass hardware (even if polished rather then corroded) doesn’t fit with either of the last two remodels the bathroom has undergone; one from previous owner, one from us. The hardware isn’t available anymore in any color, and paint would quickly scratch off, so this was a great excuse to try powder coating. I picked up a $5 toaster oven, power coat gun, and grey powder coat. Results look great and it seems like it will be plenty durable.
*Replacing/Interfacing to this with an ESP/Arduino/Raspi may be a rainy day project.