Catalina software

I'm not familiar with those programs. However, there is one particular program I use from time to time which ran perfectly well in Mojave, and it's an absolute dog in Catalina.

That doesn't make it Apple's fault. Contact the developers of those programs, or get involved with their support community assuming they have one.

Contact a third-party vendor - Apple Support

It's up to developers to fix their stuff and keep it current as Apple releases macOS updates and upgrades. Unless you contact them that they might not even know of a problem. It may be isolated to your particular installation.

Maybe those third party apps are 32 bit and not compatible with Catalina. If so, cntact the makers of the third party apps to see if they have upgrades to 64 bit.

What problems do you think need fixing?

I'm curious as well. What problems are you referring to?