The Strega is a spring lever single boiler, heat exchange, pump preinfusion machine. A hybrid. Flushing the group can bring the grouphead temp down a bit and cool the water in the heat exchange line. I have a plumb in so the water for extraction comes straight from a filtered house line source at a pressure controlled 2.2 bars. I can choose not to engage the pump for preinfusion and preinfuse at line pressure alone. The more I flush the cooler the line temperature will be so I can ball park temperature surf on the fly on the stock no mod/no probe machine. I can hold preinfusion for full grouphead fill or release the lever at anytime to play with extraction pressure ramp down.

If by direct lever you mean a spring less lever where the extraction pressure is all in the pull down the Cremina 67 is that machine. Boiler heats up, you steam wand flush it to release false pressure, full pressure and temp builds to pressurestat limit setting and you let it idle a bit to heat the brass up. Problem is the boiler temp is set for steam pressure, which is hot, and everything gets hot if you idle too long. Bringing the brew temp down is not as easy as with the Strega.

If I understand correctly about the Strega, its group is commercial and would idle on the cool side if it weren't for the thermostat controlled grouphead heaters it has. With the HX line circulating through you can kind of play with the extraction temp but I find the thermal mass of the grouphead brass is pretty stable and rebounds quickly even after an aggressive flush. It's a game, kind of, to ball park drop the HX line temp and time when to pull the shot based on where the circulating HX temp is and how the grouphead temp will affect it. This cannot be done with the Cremina. I think it's why the pulls with the Strega have more character especially when you temp surf and play with preinfusion and pressure profile.