Help with same scene now freezing at Packing BVH nodes stage

I’ve been rendering shots (for weeks now) via a large file at high resolution with tonnes of objects etc. Rendered fine without issues.

Now, I’ve encountered a freezing issue at the BVH loading phase. It all seemed to happen after a switched the camera angle. I’ve made tonnes of space on my computer by deleting files, deleted detailed objects that aren’t seen through a Render Border and have set it to 2000 samples vs 4000. It’s also way smaller in res, rendering at 100% of 1920 x 1080 vs at 200% like before.

Any ideas on why all of a sudden a smaller scene with less going on is freezing? Thanks!