I'm writing this on Edge for what should be obvious reasons.

Whenever I try to reply to a forum post or update the main info body of an HB item, the text box doesn't appear, and it just says "Loading editor..." for all of eternity. Curiously, it works just fine in a different PC Chrome browser. I've tried turning off adblock on the problem browser, even though it's worked fine in the past with and without adblock, but that did nothing.

Are you running any Chrome extensions or a VPN? Any of those might be interfering with DDB.

I do have some extensions, but none that have interfered with DDB in the past. I know I should be using a VPN in this day and age, but I'm not.

Quote from Shonisaurus >>

I do have some extensions, but none that have interfered with DDB in the past. I know I should be using a VPN in this day and age, but I'm not.

 One of the recent DDB updates may suddenly have a bad interaction with those extensions. Try turning them off one at a time and see.

I had this problem with chrome probably 6 months ago now. I had no extensions or a VPN - it's just Chrome hated this site. I would have to refresh the page upwards of 20 times before the editor would show up - and then it would remain for about half an hour before the problem returned. In the end I moved to Firefox and haven't had the problem since.