Yes every sauna I have ever been to in Europe (spas, various gyms) have electric heater with stones on top. Infra saunas are only for cheapest installs at home and usually dont generate enough heat.
Also, 80° celzius minimum for proper saunas, I have been to >100 celzius ones and its a struggle to remain for 15 mins inside.
Another point - I consider the after-part most crucial for health benefits to me - as-cold-as-possible long shower or even better a similar dip pool. Few days after that my cold resistance is significantly higher. Just the heating of body in sauna I can reach also ie with cardio workout or free weights, which brings tons of other benefits.