Think I managed to find the culprit! It was the Dark Reader extension. Dark Reader - Microsoft Edge Addons
It was only freezing up when I was using checkboxes in the beginning, so it must have been trying to correct the colour of the checkboxes and causing a freeze.
Whitelisting evernote.com in Dark Reader has resolved the issue. I'll see if I can report it to the extension dev. Huge relief
Thanks everyone for your input!
