Ah, I'm very happy to hear that! Glad you're getting such good results. It kinda shows that what we think sometimes is a GPU issue, is actually something else in disguise.
So, in terms of the balance. They are actually pretty well balanced CPU/GPU combo. You could argue that your i5 8400 which has 6 cores and 6 threads, might max out in a game or two that are CPU demanding. But there aren't many of those that you might play. For everything else the 6 cores would be fine.
Also, do keep in mind that 100% usage on both CPU/GPU are rare. Some games won't even use a quarter of CPU/GPU resources. SO you might find a game with 30 % CPU usage and 70% GPU usage. It just means the games isn't that demanding or there is some other artificial process (like locked frame rates/Gsync etc) keeping usage low.
As
@Vic 40 Said. enjoy the new found freedom, and play your games to see what improvments there is. Maybe futher down the line you could upgrade a mobo/CPU combo to a 5600x /B550 or 12400/B660 combo, which along with your current parts give you a nice bump in performance.
edit: There is no bottleneck caused by the motherboard. CPU/GPU well balanced.