I did completely get rid of Mozilla Firefox and Thunderbird on my personal systems now.
Firefox was my main browser for many years and I used it since Netscape transformed into OSS Firefox 20 years ago.
But the Mozilla foundation nowadays doesn't do a good job in maintaining the software. Bad political choices, focus on what I consider the wrong priorities and falling more and more behind on the techical details.
I moved to the Chromium based Vivaldi browser on all my systems. It's snappier, faster and way more reliable. Hardware acceleration does work out of the box under Linux and E-Mail is already built-in (although, I more often use KMail by KDE for that).
I'm highly satisfied with Vivaldi after using it for the past 6 months and never looked back.