There is no tension there.

You can care about the work and your customer will still setting healthy boundaries and accepting that wanting to do good work for them doesn't mean you are beside them.

Business is fundamentally about partnership, transactional and moneyed partnerships, but partnership still. It's best when both suppliers and customers are aware of that and like any partnership, it structured and can be stopped by both partners. You don't technically owe them more than what's in the contract and that puts a hard stop which is easy to identify if needed.