I am assuming your talking about the RX 7600 GPU card and not Ryzen 7600 APU processor correct?
Before updating your AMD Driver for your RX 7600 GPU card everything worked fine correct?
IF so then try installing the previous AMD Driver you had that worked correctly from here: https://www.amd.com/en/support/previous-drivers/graphics/amd-radeon-rx-7000-series/amd-radeon-rx-760...
If everything works fine as before with the previous driver install open a AMD SUPPORT TICKET and see what they suggest from here: https://www.amd.com/en/forms/contact-us/support.html
It is possible the latest RX7600 Driver has made some changes in Radeon Settings that is affecting your PC in running 2 monitors at the same time.
NOTE: You can also do a Windows Restore before March 20th and then see which AMD driver you have installed at that time and let AMD SUPPORT know.