You might find this episode of Huberman Lab[1] helpful. He goes in depth on current research about why deliberate heat exposure benefits our bodies and how you can use things like saunas to trigger the benefits. I listened but didn’t pay too close attention to practices because I don’t own a sauna, but I’m fairly sure a lot of the content would be helpful.

[1] https://hubermanlab.com/the-science-and-health-benefits-of-d...

Go for break once you feel you're done, go take a dip in a lake or roll in the snow (or a cold shower). After that, another 10-15 minutes in the sauna should feel nice. Repeat if you feel like it.

Here in Finland, it's customary to enjoy a cold beer in the sauna as well (or more, but that kinda nullifies any health benefits). Cooling your mouth down makes the sauna experience better -- if you don't want a beer then sparkling water will also do the trick.

I've been listening to Rhonda Patrick's podcast, FoundMyFitness. She's a Sauna buff and cites studies saying 175 degrees for 20 minutes 4-7 times a week is the sweet spot in a "Finnish Sauna" (ie not infrared)

Real benefits start after the body starts feeling uncomfortable. Don't push it too much after that. Cool down, repeat 2-3 times.

Have you tried alternating with refreshing cool showers or baths? That’s what I really like about sauna.