how can I find version 5.3.0

I am trying to uninstall 5.3.0 and do not have the original code anymore - so I cant upgrade either - can anyone help please?

OS? ?

This should be what you’re looking for:
https://downloadarchive.documentfoundation.org/libreoffice/old/

However, upgrading to the latest version is a recommendable practice …

I suggest you to use the latest Still version: it is the LO 6.4.x version today.