Umbrel is making an automated SCB copy of your channels every time you open and close one in this location
/umbrel/lnd/data/chain/bitcoin/mainnet/channel.backup
Same file is also uploaded to a cloud server (encrypted with your seed). From there, Umbrel devs can retrieve it for you (in case you don’t have a copy), but only if you provide the seed (so they do not have control of that file, it cannot be restored without your seed).
But is good that you are doing yourself a manual copy of that file into a safer location (external drive, USB memory, password manager etc), every time you open and close a channel.
Is not necessary to do it every time you do a tx. For that you can setup a Watchtower (see the troubleshooting manual - section about watchtower).
Here is also a guide about how to restore your node in case of SHTF.