I've been using Magic Earth for navigation, it's not FOSS but still has a lot of strong vouches in these sorts of communities, I believe their privacy policy has been thoroughly vetted if I recall. Works great and does what it needs to do.

For Gmail, I highly recommend Tuta, fantastic service. Paid plans are very affordable. The only thing I wish their client had was more in-depth rule customization but I may just be stupid. Admittedly setting up email forwarding from my gmail accounts has made me a bit lazy in fully switching over every single account from gmail to a tuta address, but I'm getting there.