I've checked that option couple months ago. If I remember correctly: rtags was slow, incomplete (you need extra packages for example to follow header files/auto complete header files), with more complicated project you end up with .dir-locals.el, it had problems with switching between desktop/embedded (yocto) builds, overall complicated setup. So many issues with rtags that I didn't even bother to check how it works on windows. I have experience with QtCreator and I would like to reproduce this in Emacs. You open CMakeLists.txt and everything just works.
So I've played with this some more. I've cleaned up everything, sourced environment-setup from my sdk, configured project with cmake, and now rtags-find-symbol-at-point can't find <iostream> (which is somewhere under /opt/etos/1.2/sysroots), rdm complains 'handleInclude failed (nil) ...' (https://pastebin.com/u39EGzdX).
I've tried to setup rtags once again to provide detailed info, but I get:
"RTags protocol version mismatch. This is usually caused by getting rtags.el from melpa and installing a new rtags build that modified the protocol. They need to be in sync."
Anyway, I remember that I had negative experience with rtags.
Ok, I've got it running. So the problem is: rtags-find-symbol-at-point opens wrong header files. I'm using custom sdk for embedded target generated by yocto. I need to be able to switch back and forth between desktop and embedded targets. Is this use case supported by rtags?
You might want to try asking https://emacs.stackexchange.com/questions/ask or https://www.reddit.com/r/emacs/ though