I deleted most landing challenges, extra liveries for A320, A747 and other default planes, bushtrips, training flights in Msfs 2020 content manager.

I thought that might improve the loading time but I noticed that it did the opposite, the loading time increases.

I also use add on linker for airports, utilities  and planes I need for a flight so the community folder is not overloaded.

any ideas how to improve that, thanks

I use Msfs2020 deluxe, 

intel 9900k cpu, 32gb ram, rtx3090 

On my own experience, trying to simplify/reduce both the number and the complexity of the add-ons currently installed in your community folder helps a lot in reducing the sim loading times. I *always* try to avoid using photogrammetry add-ons for example, that could add as many as 9 GB of data on a single add-on, that's what I mean by complexity.

Other add-ons, like AIG Traffic, even if they're very nice and good, could also increase your loading times if you're adding too many flightplans and models to your traffic. The same happens with the freeware AI Ship Traffic. I don't mean or suggest not to use them, but just be aware of their side effects.