Protonmail is my choice, it supports client-side encryption. Custom domain $5 a month - unlike Google you are not paying with your private data.

https://protonmail.com

> Few bucks a month add up and can be considered expensive by many.

I pay around 3$/month for Fastmail, I don't think it's expensive, an email address is the primary communication method everyone uses nowadays and it's useful every day.

I have all my mailboxes with gandi.net. Each domain you buy from them comes with 2 fully managed emails, and I think 3GB storage each, for just over $1/month. I basically never get spam, nor blocked emails. They have 2 webmail interfaces too, but I don't use them. As a bonus, gandi financially supports a ton of open source projects, which never hurts.

I use https://mailbox.org/en/, it's from a small German company and I can use my own domain with the smallest plan for just 1 € per month. Their spam filter also seems pretty good.

If you're not paranoid about Russia, you might consider Yandex Connect. It supports custom domains and has free tier with ads in the web interface.