How to Reduce the Number of Files in /preview?

In /data/appdata_<some_letters_and_numbers>/preview I have almost a million files. How can I reduce the number of these files? In fact I have in my NC stored only appr. 300 thousand documents. I would like to reduce the number of previews on lets say only the 1000 last changed files.

NC version 29.0.1
PHP version 8.2.19
Postgres version 13.14
Linux 5.10.0-29-amd64 x86_64
Apache version unknown, but I think it’s up to date

Read article about preview:

Previews configuration — Nextcloud latest Administration Manual latest documentation

I think you can only disable it.

Can I delete the files in /preview? Or would deleting the files cause malfunction of my NC?