General Opinions on Acceptable/Reasonable 4K Bitrate and Overall File Size

Hi all i am trying to grow my Movie Library after loosing my old collection and wanted to get general opinions on what you think is a reasonable bitrate and file size for 4K+HDR+Atmos as to not have a bad video experience and not eat up disk space fast. Im new to 4K and HDR and Atmos and will be buying a 5.1.2 Setup with 65inch CX or G1 TV hopefully soon.

Thoughts. for bitrate i have no idea but file sizes im thinking along this lines.

1080p - 5/10GB
4K - 15/20GB 25/30GB MAX

Bitrates i have no real idea.

Would love peoples ideas if possible. I will be using a PC via Kodi on Local storage