When vim plugins change the effect of K, all they're likely doing is setting keywordprg¹. You can do the same yourself, fex to display info on the commit under cursor you'd use "setl kp=git\ show". You can write little script wrappers to fetch whatever custom resources you want, or you can up your game by writing vim commands so that you can use a count prefix to influence behaviour of the fetch too.
¹ https://vimdoc.sourceforge.net/htmldoc/options.html#'keyword...