I'm getting about 100fps with all graphics settings on max, but CPU is averaging 50% and GPU 80%. System i6700K, 3060Ti, 32GB 3600RAM, Win 10.
Some map areas I'm getting 40fps, and the usage never increases. None of the CPU cores ever goes above 75%.

Is this behaviour normal for this game or do I have a bottleneck somewhere? (I know the CPU is bottlenecking the GPU to some degree, but that's not the problem here).

Lot's of people have performance issues with this game. They haven't fully optimized the game yet.