Your project: 890 items, Text, loads in 364s.
My project: 250 ish items, a mix of Text and XML formats, loads in 25s.
Your project is 3.5x as big as mine but takes 14.5x as long to load.
That’s probably quite relevant.
Also, if you want to try pre-unzipping your plugins, I wrote a shell script to do it (semi) automatically: Unzipped Plugins - still possible? - #51 by Mike_D
Edit to add: if you have the 2019 16" MBP, there is apparently a problem where using an external monitor causes the GPU to run hot: https://forums.macrumors.com/threads/16-is-hot-noisy-with-an-external-monitor.2211747/