You say “Tutanota is based in Russia and after a period of time will disable your email service until you provide a phone number.” /End Quote
Tutanota is based in Germany, not Russia. Have no idea where you got your information.
The site is open source (good news) and has a nice free plan including encrypted emails..
I have been using it for about a year now with no problem. Never been asked for an phone number, never been bothered by spam or excessive emails from them (other than couple talking about new features coming).
https://en.wikipedia.org/wiki/Tutanota
Where are the Tutanota servers located?
The Tutanota servers are located in secure data centers in Germany. All saved data are subject to the strict German privacy protection laws. Independent of that all data is end-to-end encrypted and cannot be read by the Tutao GmbH as the provider or by any third party.
https://tutanota.uservoice.com/knowledgebase/articles/470707-where-are-the-tutanota-servers-located
The only thing Russia from Tutanota was they tried their hand at parody and tried to make a joke about Trump switching to them for their email. It sorta backfired as a joke...
https://tutanota.com/blog/posts/trump-family-encryption
You are correct. I got my mail services mixed up. It is Yandex from Russia that wants a phone number.