I do not use big email service providers. I run my own email server. Even if you cannot run your own email server, there are plenty of email providers which do not require you to provide a phone number. But I do not recommend people to use any big or small email service provider but to run own email servers :)
Discussion
Running an email server is kinda bullshit though cause of all the SPF and DKIM DNS stuff, DMARC reports you gotta keep up with, plus they gotta have static WAN IP, and will start with low reputation score so Gmail et al will filter messages until enough recipients tell them its not spam.
But if like a steep learning curve and lots of maintenance then go for it. (I use mailcow dockerized in a VM on my local on prem server)
This, unfortunately.
I run docker-mailserver, but I also have a paid forwarding / delivery service for when I need to interact with Gmail users and big corporates.