I'll give you credit for being an engineer, but your field of expertise obviously doesn't include saunas. They are all hot and very steamy / humid / damp.
Cranking the heat up past 150F and adding steam will totally trash out your bathroom walls, floors, wiring, fixtures, cabinets, etc., etc.
That's why they make saunas out of masonry, tile, teak, redwood, etc.
Even if the steam wasn't added, heat that high will dry out cabinet wood, etc. badly and cause it to fall apart much faster than at normal temps / humidity.