Alright! After quite a few hours of research, trial & error… I found the solution!
How to Restore Funds from a Dead LND Node 🕵🏼 \ stacker news ~bitcoin – Nicely explain in here! Used Sparrow to recover my funds.
Apparently, Umbrel cannot find some Taproot addressed, so you need to do it with Sparrow (for example) properly configuring it!