GPU bottlenecks are desirable. You WANT to have your GPU running at 100% while your CPU runs at 30%, that's ideal. This way you can keep background applications running and things remain snappy even if you're playing a game.
What you should be scared of are CPU bottlenecks that can cause stuttering/skipping/freezing etc because your GPU is pushing more frames than your CPU can handle causing a lot of weird problems.
r5 3600 Will be a great CPU to pair with 1650S, although the GPU is what will be your bottleneck, you can upgrade to a better GPU an year down the line and your CPU will still be good enough to not bottleneck it.