Single Player Instant Server Hang

[Jaymasta3322]

I have come to the end of my knowledge of troubleshooting this issue I've been having.  When I load into my single player world, the "Host Not Responding. Possible causes: Server overloaded or crashed" message immediately pops up.  It seems like the server just hangs on the first or second tick.  If I change the startup command in serverconfig to "StartupCommands": "/debug logticks 200", it might trigger a single time before it infinitely hangs.  This this the 3rd time this has happened to a world of mine with the mod list that I have been using, so it seems like it is consistent.  The first time it occurred for a world, I had around 40 hours of play time in the world; the second world there was around 10 hours of play time, and in the third world now I have 15 hours or play time.  I have had absolutely zero client-side lag or fps stutters for the entire time playing (near constant 120 fps).  Even when the server is disconnected, I still have no client stutters - there is just no block updates happening, obviously.

The kicker is that if I completely remove ALL of the mods from the mod folder, the problem persists when I load into the world with absolutely no mods.  I checked to make sure the cache folder was empty as well.  I have tried deleting the serverconfig, clientconfig and servermagicnumbers files also, and the problem still persists.

Memory usage also seems normal, and stays at the same amount used after loading into the world, so I doesn't seem like a memory leak or anything.  It just seems like whatever the server is trying to do is just getting itself into an infinite loop and never resolving the tick.

Is there another command or something that I can use to see what the server is about to try to do?  I just have no idea how to troubleshoot this if there is (from what I can see) no issues in the server logs.  The only odd tick thing I can see that is occurring in the log files is the final "[Warning] Over 400ms tick. Skipping 632 physics ticks." right at client log-in, which seems to happen even when the server was working normally as well.  The occasional single tick that logticks logs seems benign as well, with no hint of what could be causing the hang.

server-main.log server-debug.log serverconfig.json