Dual channel doubles the bandwidth. So in most games, there's very little to no difference for the older Intels as the games can't saturate bandwidth demand from even single channel. Stuff like video editing uses massive amounts of bandwidth, so dual channel or quad channel bandwidth size can make a huge impact in speeds.
Since many users are now streaming videos, doing some sort of tik-tok home vids etc, and modern cpus can benefit from dual channel use, that's become a priority.
But realistically you'd have to look at the big picture and ask if it's worth it. You'd spend out cash on ram, only to turn around and need to replace it with more/newer/faster ram later.
Or would that cash be better used as saved towards replacing the platform. If it's only going to take a month or 3 before replacement, I'd save your money, no real point in trying to band-aid a busted platform. If it's going to take much longer than that, maybe it is worth it. Only you can decide that.