For H.264 and H.265 media, what bitrate and file size is as close to original quality as possible or the same as original?

I recently started building a movie/show collection again on my home NAS.

I know that generally H.265 files can be 25-50% less bitrate than H.264 and be the same or better quality. But what's the golden zone for both types? 10 Mbps for a 1080p H.264 movie? And would it be like 5 Mbps for H.265 1080p to be on par with H.264? What about 4K?

For file size: would it be 25GB for a 2 hour 1080p movie to be near or at original Blu-Ray/digital quality?