Policy to set startpage not working on first start / Linux

Hello, I am using firefox 126.0 on linux mint 21.2 with an policy file in the directory "/usr/lib/firefox/distribution/policies.json". This is just working fine with one little problem. When opening firefox the first time, it does not apply the policy to set the startpage to the url in the policy file. All other policies seem to be applied correctly. I figured out, that at the first start of firefox, no user profile (folder) "~/.mozilla/" exists. When i click the little "house" button on the the top besides the refresh buton, the correct startpage is shown. After the first start this folder is created and then the policies work fine even the startpage shows up directly. Can I somehow use a template profiles-folder for new users, so they have the correct firefox feeling at the first start or is there something missing in my policy file ? The policy file has rights set to "644 root:root" Image of the policy file is attached because I can't upload files other then images. Thank you.