Looking up and adding new expressions is very slow

[halfdanrump]

Problem

I've used this wonderful plugin on several machines before, but for some reason on my current system it's very slow. Normally the green "Add expression" button show up immediately after hovering over a work and pressing shift, but now it takes up to 20 seconds before the icon appears. Also, adding a new expression is usually instantaneous, but this also takes upwards of 10 seconds now.

Of course I'm not certain that this is a problem with the plugin, Yomichan or Anki itself, but I thought I might as well start here.

Versions

Yomichan: 21.2.28.2
Anki Version ⁨2.1.42 (8eebfe18)⁩ / Python 3.8.6 Qt 5.14.2 PyQt 5.14.2
Firefox 87.0 (64-bit)
Mac OS 10.15.7