I have a iMac Retina4K from the end of 2015 with 3.1GHz Quad-Core i5 and 8GB DDR3. My OS is catalina and I am using Firefox, Adobe InDesign and Adobe Illustrator most of the time. Since I upgraded to Catalina my Mac is soooo slow that starting the mac at morning until anything really runs (I am able to click on an app) takes up to 10 minutes (no application opened yet).

Opening up Illustrator works in 6 of 10 times, else it just freezes. If opened it does work okay though. Firefox freezes also on a regular basis. I never open up more then 3 applications at the same time, have no widget etc running and I got hundreds of gigabyte diskspace left.

I get it, that this isn't the newest device but shouldn't the OS and some really simple task like opening up a browser be "there" in less then 5 minutes?  

My question though is a different one: If I'd set up/reinstall the Mac completely new with Catalina (as I am bound by Creative Cloud to it) should that speed up my described routine or is the current scenario just what I can expect from the combination of that hardware/software combination?