I've used many, many different extensions in several different browsers over many years. (I'm an experienced web developer, starting when the web was first invented, and can code several different web languages -- in other words, I'm not a newbie.)

ContextSearch web-ext has the most complicated, buggy preferences interface I've ever seen in a browser extension. I have it running in both Firefox and Chrome, and when it works it's great -- but trying to customize it, add search engines, etc. is a nightmare.

Currently one of the engines in my ContextSearch list is "Google Maps". It works fine in Firefox, but doesn't work at all in Chrome, just leads to a blank page. So I tried exporting it from Firefox into Chrome. Forget it! The export/import features in the extension's customization interface appears to just export the URL for the icon, not for the search engine itself? And some of the gazillion preferences-interface elements for this extension, in both browsers, appear as just solid gray blocks -- regardless of what theme I use, or whether Dark Reader is on or off, or what other interface options I choose for ContextSearch itself. Of the options (including links) that I can see clearly, most of them don't do anything like what their name implies or what I'd expect them to do.

I haven't given up on it because, for the engines I finally get working, it's very useful. But I spend more time wrestling with this interface than with all my other (many) installed extensions put together!