Is it possible to install a previous version of iMovie that's compatible with Mac OSX Catalina?

My Macbook Pro is a 2012 model, meaning it is not compatible with Mac OSX Big Sur. So I have avoided installing it, despite my computer pestering me with the update notification every day. I need to use iMovie for a project but apparently it updated in the background some time ago and now it is not supported by Catalina, so when I try to open iMovie I get an error message prompting me to update my OS which is obviously not an option. Is there a way to install a previous version of iMovie so I can use the program still or is it a lost cause and I should just uninstall because I won't be able to open it again? Worst case scenario I will install some other video editing software but I really don't want to just for this, I should be able to continue using iMovie.

I tried to get tech support from Apple directly but my serial number was not compatible and I could not find anything on their website that was helpful.