As for email, why limit yourself to just one? If you really want to dump Gmail then buy a domain and sign up with the email provider of your choice. It isn’t expensive and is easier than you think. Then you aren’t platform locked at all.

I recently decided to give up and start divesting from the other accounts.

I will likely keep the iCloud Mail account, since I use iCloud for contacts, calendar, etc.. but it’s only my dad and a few accounts that it’s used for these days.

When I went to ProtonMail, I religiously tracked every time I used it anywhere so I should be able to unwind it.

I want to divest from Google as a whole, I even pay for Kagi. However, at this point it would be impossible to actually delete my account. All I did by trying was complicate my life and confuse everyone. I told my family to use iCloud to email me and my dad was the only person who actually switched. I suffered in this purgatory of email providers for probably the last 10+ years before recently coming to my senses.

I do just use the email though. I don’t use Gmail as the reason to use all of Google’s information management stuff. I don’t use Drive, Docs, Keep, Tasks, Contacts, Calendar, or any of that other stuff. Gmail, YouTube, and Maps (for points of interest and business information… not navigation). Early on with the iPhone where were weird sync issues when trying to use Google Contacts with the Apple apps, due to some different fields in play, so I moved away from all of that and never looked back. In my personal life, the crossover between mail and calendar is pretty light, and I only send email to a few people where contacts integration also isn’t a big deal.

I did have about 5 alt gmail accounts. I did recently go through those, migrate some accounts, and delete those in full, so that was nice. But most of them had been sitting largely unused for 10 years, which made it easier. I’ve also been using the same password manager for nearly 20 years, so that was also a huge help.

iCloud email just uses standard protocols and can be used with any email app. You just have to go on the web and create an “app specific password”

https://support.apple.com/en-us/102654

But why move to iCloud? I even use Apple’s Hide My Email with my yahoo account.

Firefox said on the most recent update that it also offers email aliases (but forward to what? I didn't check)

There are also some security features (in settings) standard.

I tried to stop message threading, but Apple Mail still offers "context", which tucks a previous message below the current one. In my case, I replied to an individual in a group message, and they replied to me individually, but it looked for all hell like the reply was to the group, which was an embarrassing optical illusion.

I really ask email to do as litte as possible.

A lot of my (extremely long) Apple experience consists of turning off gratuitous features that interfere with my workflow. But mail is reliable, and also accessible at icloud.com (log in) if you enable icloud web access.

You don't need to have an iPhone or other Apple device.

Neither. Purchase a domain, sign-up to Fastmail, point domain at Fastmail, install mobile app. Thats it.