This can be quite difficult, I think you may need to read this whole thread (twice) to work out a recovery plan. OnePlus - 9 Pro - lemonadep - Documentation Suggestions
“Qualcomm CrashDump Mode” is not a “bricked” situation, or perhaps is “soft bricked”, the methods in the above link will lead to recovery.
I notice that you link the install page in your OP; there is important information in this page https://doc.e.foundation/devices/lemonadep/upgrade, regarding to upgrading of the underlying firmware.
Warning: Please note this upgrade build could not be tested as there were no device specific testers available. Some devices may need a revert to stock ROM prior to upgrade.
If you are more keen to “just recover the phone” please read https://community.oneplus.com/thread/1541327 (again twice !)
- There are some supporting links shown in this file https://onepluscommunityserver.com/list/Unbrick_Tools/OnePlus_9_Pro/README.txt