Industrial Combustion Turbine - Researched
Steam Engine - not researched??? (and no way to do it - no prerequisites in Technology Tree)

Without Steam Engine there is no way to craft Combustion Turbine.

Post a save file.

https://drive.google.com/file/d/17klnf-BwsurwJEmiL_srvj_t8nJLUnRX

There are many different incompatible overhaul mods enabled.

Exactly why the steam engine is missing from the EI "Electricity power" technology (as well as it's other usual recipe unlocks) is unclear—AAI appears to have modified the technology, and Cerys has done something to the Steam engine recipe.

At this time other overhauls and third party planets are unsupported—would recommend disabling mods until things improve.

Best of luck.

I installed ESIR when it was around version 1.2.00. Back then, the "Dependencies" tab listed more mods as "Optional." I also got planets from there.
The only mods that weren't listed were "RPG," "HandyHands," and "FactoryPlanner." They don't affect the Tech Tree in any way.

Now, as far as I can see, all planetary and overhaul mods have been removed from the "Dependencies" tab.

That's sad)

Those dependencies were added by Eliont to the ESI branch to affect load order.

Dependencies overall were eventually re-organized so as not to be misleading—many being relegated to "hidden" dependencies to help them load together with EI at all, while trying not to claim to support them either explicitly or implicitly.

What remains are concrete integrations and synergistic suggestions.

Nevermind, it was AAI Industry indeed)
Steam Engene appeared after AAI Industry deletion.

Thanks for routing me)