Pools and sauna's are amazing for after workout sessions, but i have never gotten into an ice bath or a really cold pool.
When i used to live in Cornwall in England next to the beach, after a gym session i used to get into my wet suit and get into the sea to relax lmfao
idk if it was healthy but it was so relaxing, after that i used to just lay down on the sand for a while (this was when i used to surf a lot and sprint on tracks for hours when i was in high school)