https://docs.lightning.engineering/the-lightning-network/payment-channels/lifecycle-of-a-payment-channel
You can review the above under closures non-cooperatively, as well as documentation on HTLC contracts on step 4 here: https://docs.lightning.engineering/the-lightning-network/multihop-payments/hash-time-lock-contract-htlc
(Like if Alice and Bob open a channel and Bob goes offline, Alice can force closure and usually funds are returned onchain. Bob won’t be able to recover those funds if he’s lost his backup and can’t access his node and they’re lost).
For this if you recovered your seed phrase you should have been able to select from the new automatic backups feature shown here, recovering also closes your channels and returns them to your onchain Bitcoin wallet, this can take up to two weeks sometimes.
If you wish you can also rescan your UTXOs, to do so you can follow these steps:
Step 1 - Enter using SSH into your node:
Step 2 - execute the following command to rescan wallet’s UTXOs:
sed -i "s/\[Application Options\]/\[Application Options\]\nreset-wallet-transactions=true/g;" ~/umbrel/app-data/lightning/data/lnd/lnd.conf && sudo reboot
Step 3 - Wait some time so LND can rescan all wallet’s UTXOs. If it solves the issue, run this to stop it from rescanning on a future restart:
sed -i "s/reset-wallet-transactions=true//g;" ~/umbrel/app-data/lightning/data/lnd/lnd.conf && sudo reboot
As a heads-up this process may take some time, it can take upwards of 24 hours to complete.