Did you update everything in the content-manager, delete the rolling cache and did you turn ai traffic off?
I have a similar rig. Did not test heavily, but the newest update seemed ok, CTD wise.
Also read:
https://flightsimulator.zendesk.com/hc/en-us/articles/360015893879-Crashing-CTDs-issues,
https://flightsimulator.zendesk.com/hc/en-us/articles/360016027399-KNOWN-ISSUES-Last-update-July-30-2021-,
Radeon 5700XT Driver Timeout - #169 by Seven7Tango ,
Crash to desktop without error message - #4995 by MichaMMA