Packagemanager seems to be awesome -- I was also having an error installing xgboost, and I just used the exact same thing, and it worked!
I first tried to install the toolset, but that did not work - I got an error This system is not registered with an entitlement server. You can use subscription-manager to register., but I don't really understand what that means.
The Developer Toolset has to be manually enabled with every session, but you can permanently enable it using a startup file like this: https://access.redhat.com/solutions/527703.
Still didn't work...but I definitely plan on using the packagemanager binaries when I can.
When a version that I installed through the packagemanager gets updated, will I still be able to update it like I normally do (through the pane in RStudio)?
Yes, but you'll have to set packagemanager.rstudio.com as your default CRAN repo, or it'll still update packages from the default CRAN mirror. In RStudio, you can set this through the Packages options - see "Using Packages Inside RStudio" on this page for an example: Posit Package Manager