You will be fine with the 3600. A faster CPU on a slower GPU won't cause any issues.
Bottleneck is just the slowest component of the system limiting it from performing better.
In your case your GPU is your limit, however this doesn't mean your system will be slower, it just means that if you are running a GPU intensive task, you are limited to how fast your GPU is (which is the case with any GPU).
There are people running 3070 3080s on those CPUs. The 3600 is a very good value for the money, don't consider upgrading until you are limited from having a card that too fast.