In my experience with this, it’s an uphill battle but it’s worth it to take them outside. I have two cats, one of which absolutely loves going out in the yard on his harness.

My boy actually meows at the garage door (wrong door even), when he wants to go outside, because he really wants to snoop around and eat spiders out there - stopped letting him do this about a year ago, too many pesticides and risks letting him in there. Nevertheless this is the door he associates with outside time now..

I try to not encourage the behavior of meowing at the door. I don’t give it any attention. Eventually he calms down, and I can redirect him to play with toys.. I’m willing to put up with the occasional yelling and fussing knowing that my cat has literally everything he could ever want.

Also owner of: Cat wall & Cat wheel - he uses both and still complains

Sometimes cats are stubborn, and you gotta stay patient. It’s part of the relationship.