Importing macOS Caching server data from an external Mac caching server
I would just set up the second Mac and let them peer for a while. In the past it was likely to invalidate the entire cache by trying to move it or even restore it from a backup. The new commands you listed are intended to do precisely what you seek.
I’ll update if I test this, but I would assume several things:

It likely won’t matter if afp or smb shares are used if you try to move content via file sharing. SMB slightly preferred as it’s the new standard.
I would disable caching services before attempting any utility move.
I would move the cache to an external drive and then eject / move / absorb it to the new machine. (I almost always store cache on an external drive anyhow)
We put one cache server on every network segment, three or more on big network segments. With 100 or so, we do as little configuration as possible - no peering or parents have been needed yet.

With two or three caches - they rebalance each other without even needing to set up parent or peering configurations, but if you have massive clients to serve, you can make very sophisticated hierarchies with parent specific hash settings to maximize cache space or minimize lossage and internet when one node should fail.

https://support.apple.com/guide/mac-help/use-multiple-content-caches-on-mac-mchle150fb54/mac