I don’t remember how to limit the amount of listings shown on a listing block…
on my homepage I had added a listing block of 100 and I believe that is the reason why the page takes so long to load.
I would like to change the number of listings shown.
You might be meaning the Regular Listings per Page option under HivePress > Settings > Listings
If not; from the screenshot you’ve added it looks like you’ve possibly just customised the block Settings. In that case, just visit the page (homepage?) in the backend of WordPress > Pages, edit the page, choose the block, in the sidebar options; edit the number there.