Yes, npubx is the beta release of the new version. A lot has changed under the hood, but the ux is very similar. I have been using it for a long time now
On cashu.me I see two npub cash references: the npub.cash for an ln address and an npubx.cash under experimental features.
Is the second one the new version? How are they different? Maybe nostr:npub12rv5lskctqxxs2c8rf2zlzc7xx3qpvzs3w4etgemauy9thegr43sf485vg can help here.
Discussion
I see you have your name instead of the random npub in the address, would that be possible to do somehow? With cashu.me?