Difficult cold start

How about posting pictures? Perhaps a video with audio of you trying to start the engine that shows the carburetor linkage? I see many videos on youtube of people trying to start older cars. They typically just turn the key without working the throttle and it takes a long time to eventually crank. These things are obvious to us who grew up with and continue to operate carburetors.

The starting fluid you sprayed added fuel in a very easy to burn condition for the ignition system. It does not indicate exactly what the problem is.