This causes incompatibility with Krastorio2 that causes steam-engine power output to be unscaled. (at least when lowering target UPS)

Yes, in the file config.lua one can add "max_power_output", after line 187 in prototype_power_rates = {}. Otherwise no matter the target UPS the Krastorio2's steam engine output 750 kw ( instead of x4 at 15 UPS ) which makes the game way harder than intended !

Using this mod for 15 target UPS does wonder for the temperature of my potato laptop when playing, thank you !

Have the same problem with Space Explore without Krastorio. Using the burner generators are much more efficient at 20 FPS rate, also using tiered gas generators to burn oils as fast as it is possible. However it is quite a limitation and malfunction in the game progress as steam engines are intended to be more efficient.

Of course it is possible to edit by hand, but if I'm to use the built-in mod synchronizer it must be included in the official mods. Otherwise I have to distribute the modified mods myself which I would like to avoid.