No compression and sepaseparated radiator

Hey all, new to 6GA forum and I just got a 2000 coupe with the 4banger.
I have a problem that I am sure will be solved when I yank the head, but wanted to see what kind of guess you guys might have on the root cause.
This car had a rebuilt head, cam, and cam gear at 139k with new bolts, thermostat, water pump, timing belt cam and crankshaft seal, etc.

Had a new distributor due to oil in the distributor and rough running at 159k

Overheated at 160k and got a new radiator and diagnosed with a weak head gasket.

I picked it up from a kid that Overheated it with the new radiator and when I got it, the bottom tank was separated partially from the radiator.

Weird thing is that if you crank it up, after a few seconds it gets running.

There was no water in the oil and since there is no coolant I guess, no white smoke.

Ran a compression test 4: 120, 3: 60, 2: 45, 1: 120

I was just going to pull the head to verify a bad head/gasket or whatever and then make a decision to fix or replace but no water in the oil confused me.

Is it possible or likely to have a head gasket leak combustion gasses into the cooling system enough to blow open a new radiator but not leak into the cylinders?

if it looks to have a flat head and block using a straight edge would you chance a head gasket or just get one of those low mile JDM engines for a few hundred more? I'm leaning toward the replacement.

Edited because I really ran compression test with a new Schrader valve in the test gauge

I've had a pin hole leak in a head gasket before and did not see coolant in the oil, that normally only happens if it's really bad from my experience. Pulling the head and taking it to a machine shop to have them deck it is the only way to insure it is 100% true to mate to the block.
It is not super expensive to deck a head at the machine shop, heck they will even vacuum test and make sure all the valves are properly sealing for just a few bucks more, it's just added security that your not going to have to pull the head again. Lost compression normally comes from the valves not properly sealing or the piston rings being shot and or head gasket leaking.

The pressure in the system could be caused by a thermostat that failed closed and when the car started getting to temp there was no where to push the pressure created by the heat of the coolant, so it blew a end tank cap on the radiator most likely. Most times you would see it push all the coolant out of the overflow tank but if that was sealed good enough the pressure would need to escape and it chose the cheap plastic end tank to blow out of.