How to move fully sync'd native bitcoin core node to Umbrel bitcoin core node?

Sorry if this is the wrong forum for this question and if so please recommend where I should ask this. Any help is appreciated!

I have a fully synchronized node running v26 Bitcoin core on linux and I want to transfer all the blocks/chainstate data over to a new Umbrel bitcoin node running on the same machine.

Why do I want to do this?

1. It's an older computer with no ethernet - and DL is slow over wifi - so since I've already sync'd the blockchain once, I would prefer to save days' worth of time by leveraging the existing blocks & chainstate that are fully sync'd on the native version of Bitcoin Core that is already running on this machine.
2. When I have tried to just re-download the blockchain in Umbrel - it gets to like 95% (after a week of waiting) and stalls...forever....super frustrating
3. IF I could get it running in umbrel, there's way more functionality that I want to take advantage of -for example: way easier setup of the electrum personal server and the fact that you can easily point mempool.space directly at your OWN node. I'm sure that's possible outside of Umbrel, but my basic searches on github for how to get mempool to view your own personal node quickly made it clear that this requires another level of technical ability that I don't have. Umbrel would be FAR simpler if I can get the damn thing to work!

You would think this should be easy - just copying blocks and chainstate over and reindexing somehow, but that's definitely not the case from what I've seen. What little guidance is out there for people who have asked similar questions about using a previously downloaded blockchain as a shortcut in starting up an Umbrel is very specific to raspberrypi and that interface. I need to know how to do this on an actual Linux machine.