If you right click the URL bar, the context menu has options for "copy" and "paste and go".
If you left-click on the URL bar, this (correctly IMO) selects the current URL bar's contents, however right clicking in the URL bar gives you only the Mac OS (?) services menu (which doesn't seem relevant here to the URL bar and maybe is a default?)
Another suggestion is to have a separate "Paste" from "Paste and go", in case you want to tweak the URL before hitting enter. This is a niche use-case though, perhaps it is not one that would be used often enough to be worth adding.
An example user story could be if you are wanting to strip extraneous junk from a URL that you are going to share or put on a website, and want to test that it works correctly before sharing - you'll paste it (without browsing to it), do some tweaks to the URL, then hit enter.
(H/t to Maestro from discord)