Hey, i have same problem with iMac Pro with 5K resolution on Catalina 10.15 (last update) with version of TotalSpaces 2.8.5 today. No rows or columns in Preferences / Layout. TotalSpaces2 Grid inform about “You need 16 desktops” “You have 16 desktops” but i’am using only 12. Notification center send “Total Spaces 2 failed to start - please check dock, etc.”. In the System Preferences / Security and Privacy / Automation Dock and TotalSpaces have a check box.
BTW no problem on the regular iMac 2012 or Macbook 2017 with Catalina. My iMac Pro is new … recovered from Time Capsule. No vanilla instalation.
I try older version of TotalSpaces2 app, reset Apple Events, delete com.binaryage.TotalSpaces2.plist, mount -uw, etc … but without any effect 
Log from app running from terminal bellow:
iMac-Pro:MacOS mara$ ./TotalSpaces2
2019-10-25 20:41:49.888 TotalSpaces2[16151:4461109] existsInSystemPath
2019-10-25 20:41:49.888 TotalSpaces2[16151:4461109] FS allowed
2019-10-25 20:41:49.888 TotalSpaces2[16151:4461109] TFP allowed
2019-10-25 20:41:49.888 TotalSpaces2[16151:4461109] System path version 2.0.4
2019-10-25 20:41:49.888 TotalSpaces2[16151:4461109] Detected injector version 2.0.4
2019-10-25 20:41:49.888 TotalSpaces2[16151:4461109] TotalSpaces2.app is carrying injector version 2.0.4
2019-10-25 20:41:53.266 TotalSpaces2[16151:4461109] Inject called: waitingToInject: 0 injectionBackoff: 0
2019-10-25 20:41:53.271 TotalSpaces2[16151:4461109] Sending injection events to 16029
2019-10-25 20:41:53.291 TotalSpaces2[16151:4461109] Monitoring Dock 16029
2019-10-25 20:41:54.291 TotalSpaces2[16151:4461109] Connecting Dock, backoff: 1
2019-10-25 20:41:54.291 TotalSpaces2[16151:4461109] Failed to register connection
2019-10-25 20:41:55.292 TotalSpaces2[16151:4461109] Connecting Dock, backoff: 2
2019-10-25 20:41:55.293 TotalSpaces2[16151:4461109] Failed to register connection
2019-10-25 20:41:55.895 TotalSpaces2[16151:4461109] Restarting Dock because FS version was incorrect.
2019-10-25 20:41:56.203 TotalSpaces2[16151:4461109] Dock pid 16029 terminated
2019-10-25 20:41:57.294 TotalSpaces2[16151:4461109] Connecting Dock, backoff: 4
2019-10-25 20:41:57.294 TotalSpaces2[16151:4461109] Failed to register connection
2019-10-25 20:42:00.905 TotalSpaces2[16151:4461109] Version check failed. Waiting 5 seconds. If this persists, restart or re-install TotalSpaces2. 1
2019-10-25 20:42:01.204 TotalSpaces2[16151:4461109] Inject called: waitingToInject: 0 injectionBackoff: 0
2019-10-25 20:42:01.217 TotalSpaces2[16151:4461109] Sending injection events to 16175
2019-10-25 20:42:01.241 TotalSpaces2[16151:4461109] Monitoring Dock 16175
2019-10-25 20:42:01.295 TotalSpaces2[16151:4461109] Connecting Dock, backoff: 8
2019-10-25 20:42:01.295 TotalSpaces2[16151:4461109] Failed to register connection
2019-10-25 20:42:02.242 TotalSpaces2[16151:4461109] Connecting Dock, backoff: 8
2019-10-25 20:42:02.242 TotalSpaces2[16151:4461109] Failed to register connection
2019-10-25 20:42:02.242 TotalSpaces2[16151:4461109] Retry already scheduled
2019-10-25 20:42:05.906 TotalSpaces2[16151:4461109] Version check failed. Waiting 5 seconds. If this persists, restart or re-install TotalSpaces2. 2
2019-10-25 20:42:09.294 TotalSpaces2[16151:4461109] Connecting Dock, backoff: 8
2019-10-25 20:42:09.295 TotalSpaces2[16151:4461109] Failed to register connection
2019-10-25 20:42:09.295 TotalSpaces2[16151:4461109] Retry already scheduled
2019-10-25 20:42:10.907 TotalSpaces2[16151:4461109] Version check failed. Waiting 5 seconds. If this persists, restart or re-install TotalSpaces2. 3
If you have any other tips 
Thanks
Marek