Sketchup files can be problematic and the options have been discussed in this forum a fair few times. Here are some options to minimise the issues (note these are my personal suggestions only).
Don’t download the Sketchup files from within 2020 – do it from a normal web browser.
Because there are often many similar items, pick ones with smaller file sizes and low polygon counts.
Make sure you download 2015 format or earlier (2016 may work now as well).
Use the free copy of Sketchup and change/add standard textures to items. Often a Sketchup file will cause issues because of missing/incorrect textures. I use the oldest free-standing Google version which is still available if you look around but the latest web based version should work as well.
Organise your sketchup files locally and test them before using in a drawing. Any which slow down 2020 too much or crash 2020 should be discarded.
Ask for help in the various forums (here and the independent Delphi and Facebook ones) if you can’t find a specific shape you want.
Make contact with a Sketchup expert (I use fiverr.com) who could help with making/changing a specific shape for you (relay the criteria). Fiverr people are cheap.
Hope this helps.
