Ethereum does not have UTXOs nor does eMunie for that matter, account/address balances are recorded and credited/debited as per transactions they make and receive.
Without the UTXO overhead, double spend prevention across partitions is much easier to achieve and can be done in an efficient manner.
I mentioned in the video that Ethereum is using an account balances design.
There can't be any double-spend across partitions in the design I described in the video.
I understand if you want to allow spending across partitions, this complicates design issues. I had mentioned upthread that I deal with that in my design by requiring confirmation of such to wait for block confirmations. Where spending within partitions is instant in my design.
I think it is difficult to talk about every possible design variant in one video. I was already going off on too many injected tangents. That is not to say I have envisioned your design per se.
Thanks.