Firebase Unity project fails to find BoringSSL-GRPC library during Xcode build

I'm attempting to compile a Xcode .xcworkspace built by Unity that contains Google Firebase. I tried all the solutions I could find online without any luck. If you have any ideas I can try, can you please share?

The error I'm getting is that it can't find the BoringSSL-GRPC library. I tried running pod update and pod install to resolve this and I can see while it does successfully install BoringSSL-GRPC (0.0.7), Xcode still gives this error even if I open the .xcworkspace file.

ld: library not found for -lBoringSSL-GRPC

When I add use_frameworks! to the podfile per a suggestion online, I get this error:

ld: framework not found FBLPromises

When I removed the above and then add use_modular_headers! per another suggestion, I get this error:

fatal error: module map file '/Users/xxx/Documents/Builds/DemoProj/Pods/Headers/Private/grpc/gRPC-Core.modulemap' not found

Each time, I changed the podfile, I'd run pod update and pod install before doing a clean build in Xcode.

Here are the versions I'm using:

• macOS Catalina 10.15.6
• Unity 2019.4.4f1
• Firebase 6.15.2
• Xcode 11.6 (11E708)
• CocoaPods 1.9.3

And here is my podfile:

use_frameworks!
source 'https://github.com/CocoaPods/Specs.git'
platform :ios, '10.0'

target 'UnityFramework' do
  pod 'Firebase/Core', '6.24.0'
  pod 'Firebase/Analytics', '6.24.0'
  pod 'Firebase/RemoteConfig', '6.24.0'
  pod 'FirebaseCrashlytics', '4.1.0'
  pod 'FirebaseFirestore', '1.15.0'
end

Notes:

• I've also tried adding ,:modular_headers => true at the end of each pod which didn't work.
• I have a paid developer account and Xcode is configured for that account