I often do searches with multiple search engines and extras with the same query but with site:reddit.com added at the end. Being able to press CMD L to focus the URL bar, and then CMD C with all the text selected would make things a lot faster. This was added months ago to Firefox but it looks like it was removed now.
The search bar might be what you want. There is an option to turn it on in the settings.
I was able to enable it on stable by toggling browser.urlbar.showSearchTerms.featureGate
Edit: Nevermind, it doesn’t work for custom engines, which suggests that it’s a separate implementation from mobile?
I’m not sure I fully understand your requirement so this may not be what you’re looking for but CTRL+k brings you straight to search and puts the cursor in the URL bar. The engine is to the left and can be selected.
