I endeavor to be lazy so I work hard to figure out something difficult if that means I can be lazy ever after. One lesson I learned from Mark Joshi (of xlw fame) is that people give up on using your software unless it is dead simple. It took a lot of work to figure out a way to make xll easy use.
.msi Microsoft install files have become problematic, aside from the problem of creating them in the first place. If they are not signed by a Certificate Authority users get ominous warnings. After buying up all the CA companies, Microsoft figured out a way to extract even more money from software developers by inventing Extended Validation certificates that you can write a check for to make those warnings go away when using their products.
Visual Studio can use VSIX or NuGet to install packages without requiring certificates. They are almost as much fun as creating a .msi file. We now have MSIX and winget if you enjoy package management insanity.
There is an easier way.
Building software involves wrangling files that change over time. One might think that this should be a solved problem by now, but we live in a world where lesser minds have become fascinated by looking for ponies in Linus’ pile of git. He built git to solve his problem: how to merge (lots and lots of) changes into the Linux kernel code. Submodules were an afterthought and his original advice on how to implement those seems to be this.
The current version of git used by GitHub implements submodules adhering to his advice. Instead of a fancy pants package management system, you can just clone xllproject1 and it will drag in all the xll files you need to get started. Those files never change behind your back as you write new code. Visual Studio does not grok submodules, yet, so you need to start a Command Prompt (Tools > Command Line > Developer Command Prompt) and cd xll; git pull to get the latest version. Not dead simple, but the version of xll to use is under your control.