I found the culprit!
It's the db_notify_events system database, which launches programs when certain things happen. The problem is ALL of the software that can edit this system database is only for WM2003, but I found one that finally worked.
http://www.scarybearsoftware.com/cn_overview.html
The first program, Check Notifications, can do it. I found like 20 odclient calls in there, explaining the long slowdown. Even though the program reminds you again and again it's only for WM2003, it worked. I tried other database editors and db_notify_events editors and this is the ONLY one that worked, and I don't know why. Hopefully someone will make a specifically WM5 program for it soon.
This is the reason why, after disabling and exiting Odyssey Client, every time I woke up the PDA it took a long time to load and it said "error: cannot open /Program Files/Funk Software/Odyssey Client/odclient.exe" or something along those terms. It didn't happen when I shut down and restarted because the event is specifically for wake-ups and not for restarts.