As mentioned in my comment the way to filter out a long list of sites from Google search is by creating a Google Custom Search Engine (CSS). This allows you to have it customized with up to 500 sites.
How to create a Google Custom Search Engine (CSS) in 6 steps
1. Go to https://cse.google.com/cse/create/new
2. Add any name as your site in the "Sites to ...
Thanks to user marikamitsos, I've found out that Google Custom Search Engines can work for the entire web.
To do this, I had to
Go to https://cse.google.com/cse/create/new
Add any site in the "Sites to search" field (I used example.com)
After creating the Custom Search Engine, go to its configuration
In the configuration, enable the "Search the entire web" ...
I did some research but couldn't find a way round the 32 word query limit for Google specifically. Apparently, according to this source from 2017, Yahoo search doesn't seem to have a word limit so you could try that instead.