ProtonMail is the best alternative to Gmail I know.
Their commitment to privacy, the free tier, and the modern UI make it a no-brainer when looking for a valid email provider.
I've been with Proton for a long time now, and their progress and commitment to the mission is fantastic. Their product is so much easier to use than Gmail or similar too.
I have been using ProtonMail for years and I must say I am impressed with the service. The login process has always been smooth, no drama, and the UI is great and easy to use!
