I recently tackled a full degoogle. I still have my email running, I really wouldn't recommend deleting it for legacy purposes. But the tens of thousands of emails I had are fully deleted from gmail. I unsubscribed from basically everything, and hardly get emails there anymore.
I used Google takeout to get the emails exported. I had to do this per gmail account. They give you something called a .mbox file. I now use proton mail and pay for their service (I think paying makes sense for the service given the alternative is getting your data scraped for advertising revenue). I stored a backup of the .mbox file in my proton drive, and loaded the file in thunderbird (on linux with an encrypted drive) for whenever I need to search those old emails.
Overall it's pretty easy. The hardest part was a bit of Thunderbird jank for first time setup. This guide was helpful: https://www.howtogeek.com/709718/how-to-open-an-mbox-file-in-mozilla-thunderbird/
Good luck :)
I swear man, people don't hate neoliberals enough. Complete traitors to our country, and for what? Hard times require strong, courageous people to take charge and lead. The average American that voted for Harris in 2024 has more love for this country and bigger balls than these people ever will. Absolute cowards.