Greetings,
While I don't have a Z790 based board, I do have decades of experience in system building and hardware.
When you are an early adopter of new technology and hardware, there can be some pain points and instability which can also be accompanied with undesired behavior. Intel's quality has definitely taken a hit in recent years. They still lead and are my first choice.
I think its important to look at the platform as a whole. Chipset, CPU, DDR5 memory, storage etc. You've got hardware capable of nearly 6Ghz without OC. Running memory at 4800Mhz is probably good for stability and is nothing to shake a stick at. Can you get more, sure. At what price though. Do you need it? Look at the percentage of performance increase. A few hundred Mhz doesn't equate to anything except bragging rights. What are you using the system for? Gaming, Video production? Its the system not meeting your needs. Its top of class.
I'd focus on stability and reliability. I typically go with "Auto" or whatever the default is. If I need more processing power, I'd buy a newer board and processor. You are already there basically. You can lose hours / days of your life trying to tweak and squeeze every ounce of performance from your system. If you have that time, great. I don't, and just need stuff to work.
My suggestion in this case. If your system is performing well, there is no need to make changes.