I finally am able to finalize the code which makes the popup functionality works exactly how I want it to where it brings the following features:- 'Copy to clipboard' tooltip displays upon hovering over the button; Ability to have the button 'auto-' triggered and clicked without having to bring the cursor to the button itself as I utilize Vimium extension for Chromium browser. This extension allows users to open a link by typing the letter(s) associated with it; Shown in the photo above is an example.

Updated on 24 September 2020:- Synctex-searches work just fine by installing zathura and all the dependencies from the Arch official repository (libmupdf can be skipped) as long as we set the vimtex-clientserver (please refer to the first related configuration file below) which is specifically for vimtex-synctex-inverse-search. I use [1] vimtex, a vim plugin that provides support for writing and compiling LaTeX documents and [2] zathura as the document viewer.