Clearing cache from Photos app to reduce System Data

My System Data on my iPhone is 36 GB out of 64 GB. It is said this consists of cache files that the system holds on to. I know exactly what these cache files are in this case but I don’t know how to clear them. The other day my System Data was very small perhaps 5-10 GB. I took about an hours worth of video on my iphone. I airdropped the videos to my Mac. I deleted the videos off my iphone and cleared out recently deleted. When I did this I noticed that the space held by Photos was freed up by about 20 GB but simultaneously System Data went up by that same 20 GB. So my iOS is holding onto those videos in System Data. How do I clear the cache of these videos that still reside in System Data?! Yes I have turned my phone off, waited and then turned on; I have the newest iOS 17.3.1; I have cleared all other app caches. Photos doesn’t give me access to a cache. And please don’t tell me the system will release the space as I need it because it doesn’t (I almost didn’t have room to update iOS because System Data hogged my storage)