The closest you're probably going to get is --convert-links.
From the man page:
After the download is complete, convert the links in the document to make them suitable for local viewing. This affects not only the visible hyperlinks, but any part of the document that links to external content, such as embedded images, links to style sheets, hyperlinks to non-...
Desperate times call for desperate measures.
Use this utility to disable Turbo Boost and prevent the CPU from spiking power use: https://www.rugarciap.com/turbo-boost-switcher-for-os-x/
Limit total power to the CPU with this utility:
Disclaimer: I have not used either of these. However, in theory they should help.
Another tool ...
I don't own a Mac, so I can't provide a literal solution.
However, I could imagine that you are running low on RAM. In this case, the O/S (not only OS X, but also Windows, Linux and other O/Ss) begins to swap RAM contents (of other running applications or of the same application) to disk. The blocking time you describe (10 to 20 seconds) would be typical for ...