If you don't mind paying, Protonmail. I pay €12 per month for mail and VPN combined however it is cheaper if you only want the email option. I haven't used Gmail in about three years now.
Degoogling is a long and difficult process. I highly suggest you start with small steps. For example, you could start using Invidious to watch Youtube videos. It is definitely not without bugs and you will run into issues. Change your search engine to Duckduckgo or Brave or whatever else you prefer. For general searches, these are good enough. Unfortunately, for addresses and navigation, Google Maps doesn't have a good enough competitor that I know of. I urge you to make Firefox your daily driver if you are still using Chromium-based ones. I have Brave browser as an alternative for sites like banking or to access Maps or Google search. Start an alternate Protonmail account while still using Gmail. Be warned though that the free tier has 500MB, the paid tier 500GB.
If you want to go full hardcore, look into Graphene or CalyxOS as a replacement for your Android. I specifically bought myself a Pixel phone so I can get a degoogled OS for my primary phone. I still have a secondary phone running Android for banking and paying which I turn off when I do not use it. Look into Shelter to freeze apps. For example, Uber doesn't need to know your whereabouts when you are not specifically looking for a cab.
But please, please, DO NOT start doing everything all at once or you will get overwhelmed. I now almost fully use open source stuff, and I pay and donate for services. I think this is the only way to show support for the projects you love and to have a voice against big tech/ad tech.