I totally hear you on the airplanes.
Above Mach 2.75 or so, the jet engines start to transition or ‘cycle’ into ramjets all on their own. If the engine cant cope with that, it becomes extremely sensitive to throttle movements and ultimately overspeeds and maybe over heats.
Removing all other factors, the J-58 had air bypass by air withdrawal from the 4th stage of compression (which fed directly into the after burner). This allowed the engine to cycle into much more of a ramjet, and the compressor could be spooled down while still supplying power to the accessory gearbox case to power all of the fuel pumps etc.
The J58 was genius in simplicity, it was the metallurgy that made the engine work.
Yep, that’s why the spikes retracted inside.