Can Disroot Email/Webmail On Tor Be Encrypted With Mailvelope?

I’m new to Disroot and came up empty researching if this is possible or even feasible. I’m not a techie and I’ve been having to reinstall Tor from the launcher on my Linux laptop every time I open the browser. I tried to install Mailvelope from the Tor settings and I was directed to Mozilla where I installed it. So I suppose Tor isn’t designed to facilitate this unless there’s some workaround?

I’m simply trying ensure my email is as secure, private and hacker proof as possible. Does using an email alias client like Thunderbird help or hinder that goal? Does it just sacrifice anonymity for more features and storage? Is it wise to have as a backup regardless just in case Disroot email goes down temporarily? Any suggestions on how to harden my email would be greatly appreciated Thanks