How to keep browser from showing sign in screen on every launch?

Hello, I'm using AppAuth on macOS (11.2.3) in a native Swift application and it works in terms of logging into Google and using the APIs. However, every time I launch the app, it asks me to re-authenticate in the browser (in this case Safari, but I have tried it with Chrome as well), even if I just used it minutes ago. I'm using it only with a single Google account on a single machine.

Is there a way I should be using a stored refresh token on the next launch to tell AppAuth to bypass the browser authentication and just use the saved token (if it's still valid)? I can save it in NSUserDefaults and/or iCloud Keychain but I don't know how to tell AppAuth about it.

Code that I call when app launches:

func authorizeGoogleAccount() -> Bool {
	let dg = DispatchGroup()
	dg.enter()

	let serverPort: UInt16 = 62626
	let issuer = URL(string: "https://accounts.google.com")!

	// discovers endpoints
	OIDAuthorizationService.discoverConfiguration(forIssuer: issuer) { configuration, error in
		guard let config = configuration else {
			print("Error retrieving discovery document: \(error?.localizedDescription ?? "Unknown error")")
			return
		}

		let kSuccessUrlString = "http://openid.github.io/AppAuth-iOS/redirect/"
		let url = URL(string: kSuccessUrlString)

		// Starts a loopback HTTP redirect listener to receive the code.  This needs to be started first,
		// as the exact redirect URI (including port) must be passed in the authorization request.
		self.redirectHandler = OIDRedirectHTTPHandler(successURL: url)
		let errPtr = NSErrorPointer(nilLiteral: ())
		guard let redirectUri = self.redirectHandler?.startHTTPListener(errPtr, withPort: serverPort) else {
			print("Failed to start HTTP auth listener.")
			return
		}

		// Configure the auth request.
		let request = OIDAuthorizationRequest(configuration: config, clientId: kGoogleClientID, clientSecret: kGoogleClientSecret, scopes: [kGoogleDriveAuthScope, kGoogleMailAuthScope], redirectURL: redirectUri, responseType: OIDResponseTypeCode, additionalParameters: nil)

		// Perform the auth request.
		self.redirectHandler?.currentAuthorizationFlow = OIDAuthState.authState(byPresenting: request) { authState, error in
			NSRunningApplication.current.activate(options: [.activateAllWindows, .activateIgnoringOtherApps])

			if let noptAuthState = authState, let token = noptAuthState.lastTokenResponse?.accessToken {
				self.googleAuthState = noptAuthState
				self.googleAuthAccessToken = token
				print("Google auth access token = \(token)")

				if let refreshToken = noptAuthState.lastTokenResponse?.refreshToken {
					self.googleAuthRefreshToken = refreshToken
					print("Google auth refresh token = \(refreshToken)")
					kKeychain.set(refreshToken, forKey: kGoogleKeychainItemName, withAccess: .accessibleAfterFirstUnlockThisDeviceOnly)
				} else {
					print("No refresh token returned.")
					_ = self.freshGoogleAccessToken()
				}
			} else {
				print("Auth error = \(error?.localizedDescription ?? "<nil>")")
			}

			dg.leave()
		}
	}

	dg.wait()

	return self.googleAuthAccessToken != nil
}

Start with authorizeGoogleAccount and the OIDAuthState.authState(byPresenting:) call, then inspect how googleAuthRefreshToken is stored and used by freshGoogleAccessToken. Done means establishing whether the saved refresh token is used during launch and documenting or correcting the flow so unnecessary browser authentication is avoided.