AMD Ryzen 9 3900 is processor manufactured by AMD and launched in Q4 2019 . It's using AM4 socket. It has 12 cores and 24 threads with clock of 3.1 GHz that can turbo clock itself to 4.3 GHz . This processor is used in Desktop devices and can consume up to 65 watts of power .
AMD Radeon RX 6600 XT is graphic card manufactured by AMD and launched in Q3 2021 . It's using PCIe 4.0 x8 bus type. It has core clock of 1968 MHz and 8192 MB (8GB) of memory . It supports OpenGL 4.6 . This graphic card is used in Desktop devices and can consume up to 160 watts of power .
This configuration has 2.1% of processor bottleneck . Everything less than 5% should not be concerned major bottleneck.
Processor bottleneck is worse, than graphic card bottleneck, because utilization of your processor will be on maximum and it will throttle other programs that are ran in background. Also you won't experience maximal performances that your graphic card offers.
You can resolve this by upgrading your processor or by downgrading your graphic card. Downgrading your graphic card doesn't make much sense and in that case is better to leave current graphic card in you computer.