great, it works in Sparrow. Perhaps you want to update your article, I had to create 2 wallets in Sparrow, one for segwit (m/84'/0'/0' as you mention) and one for taproot (m/86'/0'/0'). Then Sparrow allows fine-grained control, so my original post is now partially obsolete. :) 

My updated workflow will be: create a tx to dummy P2WSH address in Sparrow to determine maximum sendable amount, initiate channel opening with this amount (basically the same `bos open` as in the original post) and send from Sparrow to address given by `bos open`. 

xmrk2

bitcoin

Open a channel spending the whole UTXO (no change output) with lnd & bos

Indeed, Zap desktop can import it directly the seed.
With Sparrow you need to do some additional steps.
Ah sorry, I forgot to add the link (see point 5).
https://darthcoin.substack.com/p/umbrel-btcln-node-shtf-scenario