Not sure what to do.

[Dave48]

Your bike is not going to depreciate anymore now its 14? years old BUT don't expect to recoup any further money spent on it if you decide to sell in a year or so. I completely understand where youre at-(Is the grass greener on the other side?). You  are going to have to get some test/demo rides in on a variety of bikes to decide whether theres a "better?" bike waiting for you. Shame you have to pay out labour charges to others but as you say youre getting the miles in and hopefully enjoying them.  Mods wont affect your insurance premium unless they affect outright performance-that's what my insurers tell me anyway.
good luck-there are worse mental torments than this one! :lol