It can be but requires a lot of locked up liquidity and time spent managing it. It's not an easy return if that's what you're looking for.

Afaict it depends. There seem to be more people earning by routing generally (optimizing certain routes) than leasing liquidity, but liquidity marketplaces are kind of new. APR isn’t zero but the cost of running a node worth getting liquidity from isn’t zero either.

It’s time consuming but if that’s what you want to do just be prepared to deal with technical problems

Please read first:

• https://darthcoin.substack.com/p/recommendations-for-ln-users
• https://darthcoin.substack.com/p/lightning-routing-fees-experiment
• https://darthcoin.substack.com/p/getting-started-ln

If you really want to do something good with your node, be the Uncle Jim:

• https://darthcoin.substack.com/p/bitcoin-private-banks-over-lightning
• https://darthcoin.substack.com/p/getting-started-lnbits
• https://darthcoin.substack.com/p/the-bank-of-lnbits
• https://darthcoin.substack.com/p/lnbits-for-small-merchants

Always depend, it's a market, in my opinion manage/routing is better and the key point is to select nodes base on reputation (you know the people behind) instead of one forced by market pressure. In the long run I prefer to be able to reach the owner of the node instead some random node.

From what i've heard, it's not profitable, even when a lot of time spent managing it.