Generative Fill _ Using own image library as source

We are an event design business and have all our own products. 

Im really interested in exploring creative mock ups generated by AI using only our own pieces - or ideation with our products at the heart and additional styling around them.   Have tried using our work as the source image but it strays too far.

All images are saved in our Libraries in PNG form, along withg all previous mockups.  We currently spend a lot of time layering pieces and designing mock ups but would love to see if AI can improve this process for us!  Any ideas?

The Generate/Genreative Fill funcitonality is great, but we need to be able to replace pieces with real life actual products. ideally in layered PSD so we can edit as the design progresses.