TL;DR If you're not running your own full node, you're trusting someone else to verify the ledger for you.
TD₿: Umbrel: How To Run A Bitcoin Node - Parts, Assembly and Software Installation by BTC Sessions
TD₿: Umbrel: How To Run A Bitcoin Node …
TD₿: Umbrel: How To Run A Bitcoin Node - Parts, Assembly and Software Installation by BTC Sessions
TL;DR If you're not running your own full node, you're trusting someone else to verify the ledger for you.