yes, you need inbound liquidity in order to be sent sats through your lightning channels

so when you establish a channel it’s usually 100% outbound capacity, so you can send those sats OUT from that channel

as you spend, and send those sats OUT, they then become inbound capacity (and can be sent back IN your direction)

but there are some services like Loop and Boltz where you can “switch” your outbound capacity to inbound

i think you essentially send your sats to some lightning address (giving you inbound capacity), and then they send you those sats (minus some fee) back to some on-chain address

unsure exactly how this allllll works (i’m still figuring it out), but it should be roughly correct