Other: – Heatwave temperatures, radiation tank lid opened.

Ok here’s what happened.
I started the car and turned on the heater, according to some videos I saw. I poured some coolant into the rad until the level covered the fins inside. The engine ran fine until the fan came on. Then all the coolant I had added seemed to bubble up and keep coming out of the radiator after a few minutes of shutting it off.
After inspecting the radiator cap, it looks almost new. All tires are in good condition.

It didn’t look like in the videos where the coolant level stayed relatively still and bubbled like a fish tank burst.
I think as much coolant flowed up and out like a wave as the amount I put in.

I’m confused.

As per your question above about a radiator cap looking good and bad, yes.
For this event, the fans turned on at about the same time as your thermostat opened, hence the sudden flow.
Fill your tank to the full heat line. Remove the cover of the device. Make sure there is water at least to the fins and no more. Start the engine and bring it to operating temperature with the hood off. Watch for bubbles while you wait. Get some videos to pass the time to post later while you’re at it.
When the thermostat opens, you should see the water rushing but not bubbling. If it makes a few hiccups, then it may just be letting out air. If it’s still blowing or blowing hard after a few minutes, start shopping for a head gasket job.
If it doesn’t do more than a good flood of water, top it off with as much as you can fit the cap on, run for a few more minutes, see if your tank fills up a bit with water and/or bubbles. If it bubbles, lift the front up and turn on the heat and keep running to see if it stops.
If it doesn’t bubble, cover, let cool, and tap off the excess above the full cold line.
Also keep an eye on the temp gauge to make sure it’s not overheating while doing any of this.
Another good field test is to see if your needle drops to the hot side when you hit the throttle.