So I wanted to see how scraping a large site compared with multiplexing off. I used the -http2=off parameter, but I got a segfault.
So I decided I'd configure wget2 without the http2 library and just try the same command again (without -http2=off since it wasn't compiled with it anyway) and it worked just fine. (Also.. it does seem like wget2 is faster without http2, for the site full of large pdfs I'm scraping anyway.)