My girl is terrified of her harness (but desperately needs her walks)

Any advice for a Britt who is afraid of her harness? We've tried several harnesses so it's not this one specifically, any harness scares her. Unfortunately for too long my husband and I would work together to catch her and put her in the harness so we could walk her, prioritizing the exercise over the harness desensitization. We're trying to fix that now. I've been using treats/peanut butter to try and get her as close to the harness as possible while I hold it. She's so skittish when one of has had the harness, though. Is it just a matter of patience and consistency, or is there anything else I can be doing?

We don't have a fenced in yard, can I get her enough exercise playing fetch/tug/flirt pole inside while we work through this? She's used to getting a good 3 miles or so per day, plus playtime and training.

Any advice for a Britt who is afraid of her harness? We've tried several harnesses so it's not this one specifically, any harness scares her. Unfortunately for too long my husband and I would work together to catch her and put her in the harness so we could walk her, prioritizing the exercise over the harness desensitization. We're trying to fix that now. I've been using treats/peanut butter to try and get her as close to the harness as possible while I hold it. She's so skittish when one of has had the harness, though. Is it just a matter of patience and consistency, or is there anything else I can be doing?

We don't have a fenced in yard, can I get her enough exercise playing fetch/tug/flirt pole inside while we work through this? She's used to getting a good 3 miles or so per day, plus playtime and training.