The low frequency may have to do with what the TDP is set at. The default is 15W, but it can be set to 25W.
Default TDP = 15W
AMD Configurable TDP (cTDP) = 10-25W
If possible, look into the BIOS for TDP. Increase it to 25W - if available.
What is the cpu's temperature at idle and at load? The max temp is 105C.
Max. Operating Temperature (Tjmax) = 105C
Ryzen 5 Pro 4650g, ASRock B550 Phantom Gaming 4/ac, 16GB Crucial Ballistix 3600MHz, SAMSUNG 970 EVO NVMe 500GB, Super Flower Leadex III Gold 850W