[2020] Game launcher takes an awfully long time to load

This is certainly caused by having lots of mods. I don't think there's anything you personally can do aside from unsubscribing from any you don't need.

You could mention this to the launcher developers here:

New launcher version : 2020.14

Launcher time again - This time the release is 2020.14 and it's a bit of a maintenance release as we are hammering away at some design changes in the background. Changes Improvements to renewal of authentication tokens - In short, you'll stay... forum.paradoxplaza.com
If there are any particular mods that cause it for you, mention them there too.  

The launcher developers are gathering user information on this slow startup issue here:

Launcher bug hunt thread - Startup performance of 2020.14

As it seems a larger-than-usual number of players are having troubles with startup performance, whilst we are having trouble reproducing the exact behaviour, it's time to call a general bug-hunt on this little nasty. This thread is for reporting... forum.paradoxplaza.com
Your input would be greatly appreciated there!