Can an owner opt out of paying condo fees for a part of the service supplied by the board?

In a few words, generally no.

You can read your governing documents to determine what you own in common with all other owners, including common area, common elements and limited common areas/ elements.

As an owner you are obligated by your governing documents to pay for the preservation, protection, and maintenance -- including improvements -- of all real estate elements that you own in common with all other owners -- by way of your assessments.

If you do not understand how you are responsible to pay a full assessment for the services supplied to your community and its assets, by way of your board of directors, you can discuss it with your board or with your association manager.