Email is tough because Gmail is good. But I finally found a replacement. https://inbox.lv and https://mail.ee . Both also gave me 20gb of cloud storage so that is pretty cool.
Oh by the way, I figure out Syncthing provides you with a cloudless sync solution. Which is neat since I don't need to rely on Google drive to work on my documents anymore.
Next is browser. I installed Brave Browser which comes built in with Brave search engine. So I basically able to ditch both Google Chrome (which now I only use for apps installation) and Google Browser.
For meeting, I change from Google Meet to Jitsi Meet. Which is free, and unlimited.
For Desktop sharing, I change from Google Desktop / Team viewer to Rust Desk, which did the job pretty well.
For research, I have always been using Zotero. So no issue. Problem is, Zotero local app does not work only office. First was WPS, but I try being open source, I eventually I had to install Libreoffice. Apparently, Libreoffice looks neat on ChromeOS so I don't complain.
For email client, I used Geary. it is not perfect. but it is fine. On Android I used Edison Email, in lieu of the Gmail app.
