How to sync two Macbooks and use one as a backup
After a frightful day updating to Catalina, having it freeze multiple times, and fearing that I may have lost all my files (too long a story), I need a better solution to my life. I plan to get a new MacBook with a larger screen for work and, because I really HATE the time it takes to upgrade the operating system and restore from back-up when things go wrong, I plan to keep my current laptop as a part of my backup plan. My idea is to keep the two Macbooks synced so everything I do is both places and I can stay in business if something goes wrong with one. And then I was thinking I ought to do a Time Machine back-up of one of the Macbooks that I could use for both. Is this a sound plan? Or do I need to use Time Machine on both laptops? Also, I have never used iCloud because I want everything I do to be safe on MY computer and not live in the cloud. Can I use iCloud to keep EVERYTHING except mail in both places? And only use it for that? (I do not need email to be synced -- I use Gmail on the web instead of Mac Mail (which became a nightmare). I have also considered using Dropbox. Thoughts?
MacBook Pro 13″, macOS 10.15