It sounds to me like Jay is under the impression that he is your supervisor rather than your client and that he owns you a little bit.
I would suggest trying very hard to diversify your income from clients a little so you dont rely on his work as much. Thats a bad position to be in quite frankly because as others have said, he should respect that you know what youre doing and have the expertise to do so. Im sure we have all had clients like this in the past and all agree that they are a nightmare.
Do you have a contract in place specifying a number of free revisions before you charge extra? In the past when a problem client has come back ive put in that sort of clause so that when they want tiny little changes i can say to them, i can absolutely do that but itll cost an extra $XXX for another round of revisions. They often realise that moving a chair 2inches to the left isnt worth it. Or they will spend the time to collate all of their feedback into a single round of revisions saving you both time.
Going beyond AI it seems the reason he wants AI to do the work is because he thinks it would save him money. So If thats what he wants then you should agree on a charge per apartment (or per sqft perhaps if theyre inconsistent), set a time limit per sqft and then work to a quality that you can achieve in that time. If he isnt happy then you explain that if he wants higher quality then you need more time.
Or you spend some time doing r&d yourself into workflows that can speed up your output to make the bulk of the work easier on yourself in the long run. Is there a modular approach you can take in any areas? Could you spend time creating some parametric assets or rooms using something like railclone and its splineID tools to position furniture against walls or for kitchen cabinet arrangements etc. Are there scripts out there to help already for things like mouldings and kitchen cabinets? These sorts of things could save you time and hassle and can be reused in future for other clients too and if you save yourself time, you can either pass that saving on to the client depending on how youre billing. Or you can get the client their work faster with less of a time cost to yourself.
If youre doing 200+ apartments its worth looking at your workflow and seeing where you can semi-automate things with some upfront work even if that r&d time is unbilled.
I agree with everything that has been said in this thread and last reply especially. Since we also have dealt with similar clients in the past I can confidently say that rarely (if ever) they lead to a happy place, professionally and personally. Such clients usually bring very mundane and time-consuming projects, try to pay as little as possible and ask to do the work as fast as possible. And they are usually very good at checking the limits of your work, asking more and more with each project (in your case using AI for literally any task, no matter whether it's possible or not).
It is not an easy decision to make but I would highly recommend moving away from such client because you also risk getting sucked into the similar clientele where your biggest selling point becomes speed of work with unfathomably large projects (when I read you need to model 200+ apartment buildings with interiors and all my jaw just dropped...). Personal branding takes time to form and even more time to reform.