Why is this so hard? Technology is typically a "religious" topic and it really doesn't need to be. If OP is happy with Outlook as a client, why not just go with Microsoft's FREE outlook.com service and be done with all the "what works with what" complications.
Outlook.com uses a "Microsoft Account" (aka "MSA") and has advanced security options like MFA, password-less, etc.
Linux gonna Linux and whatever - for OP, we should just keep it simple.
While I agree with most of what you said, I sometimes get challenged by MFA on outlook and it is infuriating when I am in an area where I can't use my cell phone, no service or prohibited. That is, I don't have cell service but I do have plug in internet or wifi but am locked out because the idiots in Seattle do not understand that there are places on the planet without cell service.
I think one of the things OP was trying to get away from is MFA.
Reminds me of a podcast I heard a few weeks ago about the ignorant assumptions software developers frequently make. Some examples were:
- First and last names must be more than 2 letters
- Everyone has a first and last name
- First and last names are always capitalized...
and it goes on and on.
One of my favorites is that, here in Hawaii we have addresses like 65-1234 Alakahakai Mauka. But many websites reject that as invalid saying that - is not allowed and that a direction and street type is required. Ok, morons, both of those are included, Ala is the street type and mauka is the direction. We don't do N/S/E/W. We identify an ahupua'a ("pig pile" = strip of land from ocean to mountaintop, 65 in the example) Do your homework companies before building an incorrect restriction into your software! The USPS says the hyphen is allowed in Hawaii (I've asked) and omitting it can lead to misdirection or return to sender. So companies incur extra expenses when their mail is returned because they fail to understand that different address forms apply to this corner of the USA. It is extremely common.
Sorry to drift off topic but I think it not too much of a drift since the gist of the OP was displeasure with what big providers assume we want or need.
