Ask HN: Replacement for Skype for Vid Calls To/From Mainland China?

Run a professional services biz, one aspect is job and academic entrance interview coaching. Skype is becoming increasingly less reliable and stable. I don't want to rely only on Wechat Vid anymore for a lot of reasons including privacy concerns. Zoom, I am told only runs for 45 minutes for the free version. Best case, I don't want clients to have to d'load any software. Some form of embedded encryption would be ideal. Any affordable and/or free services?