Are there any risks or disadvantages to building software from source, compared to installing a package? Can it mess with my system in any way?
I usually avoid it because I’ve found it to be a faff and often doesn’t work anyway but in a couple of cases it has been necessary.
You can disable functionality that you don’t use or want (code that is not used cannot be exploited).
You can enable hardware/kernel specific security mitigations.
You can know what source code corresponds to the generated binary.