To replace everything. Mail, calendar, drive, vpn, password manager, documents etc. What are the pros and cons relative to proton? What are the mobile apps like? What assurances do you have they won’t go full proton in the future? And other questions
I can’t find anything specific on their data security - do you have a link to that?
Maybe you can check their code at github. It’s open source, their bugs history and issues are there.