I recently switched from using Chrome to Firefox. Next on my list is probably to try to wean myself off of using Google search. Getting my email off gmail is going to be harder and not sure what the best way to do that is.
Get a second email -- potentially at your own domain so you are never again locked to any particular service -- and use it in conjunction with gmail. Sign up any new accounts to your new email, and slowly migrate others as you see fit. After a year or two, your gmail will only receive spam, and anything important will be in your new account.
There's lots of alternatives out there, but the good ones aren't free - ProtonMail is one, FastMail is another. There's others as well, but those are the one's I'd recommend. There's also Hey, but I'm still not sold on that one.
