Bypass hose

OP; you mighta mentioned that in post #1.
Time for a Cooling System Pressure test, and
a Compression Test, and possibly/probably
a LeakDown test on one or two cylinders. I'd be looking for an unauthorized connection between the cooling system and a chamber, probably/ hopefully, just a head gasket.

But before that;
do not crank the engine with the plugs in! If you are getting water in one cylinder you may bend a rod during cranking.
Pull the plugs out, looking for water, or evidence of water, especially if it has been cranking funny lately.
And check for water in the pan. Let the engine sit overnight, then drain a cupful of "oil" to see what comes out. Once oil gets into a chamber with the valves closed, the only way out is past the rings and into the pan.

I hope I'm wrong