After switching to Thunderbird I can never go back to Gmail.
https://www.thunderbird.net/en-US/
For really important mails I use ProtonMail.
https://www.thunderbird.net/en-US/
For really important mails I use ProtonMail.
I switched to Thunderbird at the same time I switched to Linux; after some tweaking, I was mostly happy with it.
Then, in some major version, it started frequently freezing up for thirty seconds at a time. Authoring emails in it became impossible. I could not downgrade it because it was version-locked with some system libraries (libnss OSLT). I could not debug it because that was blocked by a bug filed on Bugzilla ten years ago with no fixes or workarounds.
Then, in another major version, they killed XUL extensions.
I still hope to stop depending on Google services some day, but at that point I would probably switch to or write some webmail with a similar-enough UI to Gmail.
I switched from Gmail to fastmail last week, after planning to do so "one day" for a few years. Using a mixture of the web client and Thunderbird, just like I did when using Gmail. No regrets so far, I recommend taking to leap!
No, it's still there even in the most recent version. (Maybe I just have too much mail?)
Unless something has changed in the past 3-4 years.
So in short, you can use Thunderbird as a client with your @gmail.com address, so you still have the same spam filter and search, but a lighter and faster UI.