[Memory connection overburdened/Can't keep up, even with 64GB DDR4 and 16GB allocated]

I was playing in my single player world, overseeing my minions dig a mineshaft, when suddenly the fps dropped to zero, and the log displays the following:

[B#757]  2022-07-16 12:47:25 [WARNING] [Minecraft-Client] Memory connection overburdened; after processing 2500 packets, we still have 43114 to go!
[B#757]  2022-07-16 12:47:25 [WARNING] [Minecraft-Client] Memory connection overburdened; after processing 2500 packets, we still have 41343 to go!
[B#757]  2022-07-16 12:47:25 [WARNING] [Minecraft-Client] Memory connection overburdened; after processing 2500 packets, we still have 39569 to go!
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[B#757]  2022-07-16 12:48:55 [WARNING] [Minecraft-Client] Memory connection overburdened; after processing 2500 packets, we still have 755 to go!
[B#757]  2022-07-16 12:52:13 [WARNING] [Minecraft-Server] Can't keep up! Did the system time change, or is the server overloaded?

Additional info:

• The nether has no lag whatsoever, the 240 fps that I usually get.
• My other worlds have no lag whatsoever.
• Unsummoning minions makes no difference.
• /cofh killall makes no difference.
• Reallocating from 16GB to 12GB makes no difference. Reallocating to 10GB makes no difference.
• I'm not running any Tinker's Construct or Project Red machines.