Yes, the brand Tupperware is an mlm and sold directly by sales people. Back in the 50s and 60s Tupperware parties were a thing.

The confusion is likely the whole q-tip/Kleenex thing. We call it all Tupperware but really it is not Tupperware brand most of the time

K-9 is a great app but doesn’t provide email service itself

Well both have free options as well, but they have a bit lower limits in that case and a few less features. So I guess maybe sign up on both for a free account and see which you like more?

What feature set are you looking for and are you wanting something free or open to paid?

I use both Mailfence and Protonmail different experiences with each but no real complaints. For Mailfence I pay them since I have a domain and I am still degoogling so forward my gmail to an alias there