I don't want to burst your bubble on privacy, but unless you're fabricating all parts yourself... well, you just gave me a business ideaThe only problem with that is those are free email programs, and if you look in the TOS you have no explicit rights to complete privacy. Technically, with the dawn of AI, they can know what you have just by letting AI analyze the data on their servers.
If you're ok with that, go for it. Just something to consider as rights and laws change.....