If you get them involved in the design process, they feel heard. Feeling heard is one surefire way to have a person feel involved. Feeling involved fosters a sense of ownership and pride which in turn helps keep a person engaged.
Literally just a few minutes ago I had a senior architect send out a clearly Claude-generated .docx project proposal filled to the brim with stuff that is outright not permitted in our organization due to legal constraints and IT policy decisions. This guy has been with the organization for a few years so none of our limitations should have been a surprise. I got to page two before I replied that it was unprofessional to send me AI slop and expect me to be the first to read it.
Some people seem really great with AI as a force multiplier. For others their brain just shuts off entirely. Sorting out how it will affect each person is the real challenge now. We don't even mandate AI usage, it's just there if you want to use it which makes it even more frustrating. As for my approach? A one on one discussion reiterating my expectations that they remain thoughtfully engaged and if needed followed up by formal verbal warnings and then PIPs.