Hi Developing-Supremely,
We appreciate you reaching out to us. We understand that you are experiencing issues using QuickTime Player to record your screen.
We’d like to start by setting your expectations. As mentioned in the article below, "Some apps might not let you record their windows."
How to record the screen on your Mac
Are you using the same steps in the article below to initiate the recording?
Record your screen in QuickTime Player on Mac - Apple Support
If yes, we recommend that you check if the issue persists when signed in on a different user account.
The article below can help if you do not have any other user account to test with.
Set up users, guests, and groups on Mac
If the issue persists on a different user but only on certain windows, it is likely that the app does not allow screen recording.
If you are unable to screen record at all, we recommend that you reach out to us here so we can take a closer look into the issue: Get Support
Take care!