Either use Stable or Unstable. Testing is actually the most unstable of the three branches, due to how Debian works:
Updated packages are first introduced into Experimental, then into Unstable when they actually build and run. So Unstable is equivalent to Arch’s main branch.
Then they automatically enter Testing after a few weeks without anyone reporting a critical bug.
What this means: Testing is the only branch where the decision over what enters isn’t made by a human.
If someone notices critical bugs in Testing, the packages may be kicked out of Testing again until the bugs are fixed. So Testing is the only branch where packages can simply disappear when you run an update.
It’s also the most insecure branch: When a vulnerability is discovered, the packages in Stable are patched to close it. The packages in Unstable are updated to a new version that closes it. In Testing, the vulnerability stays until the new version eventually migrates down the line again after spending a while in Unstable.
I’ve run Unstable for years. IMO it’s a great rolling release distro with horrible branding.