here you can find all the compatible firmwares (direct links) for oneplus 5 to 9 pro 5g.
OnePlus EDL firmwares for all Supported models
Unbrick, Downgrade, Back to Stock OnePlus 5 to 9 pro
Unbrick, Downgrade, Back to Stock OnePlus 5 to 9 pro

here you can find all the compatible firmwares (direct links) for oneplus 5 to 9 pro 5g.