In case you’re not aware, there’s a project called VCMI which rewrites the Heroes 3 engine to add lots of modern improvements, fixes and easier access to mods. Thought it might be of interest since you like the game.
As for other games, how about XCOM? These games are turn based so you should be fine with touchpad + there’s plenty of time to think. Don’t know what specs we’re talking about but in case of modern revival, XCOM: Enemy Unknown should work without issues. XCOM 2 is slightly heavier but might also work.
You could also go for 4X titles like Star Ruler or Total War series.
Finally, there are turn-based RPGs like Knights of Pen and Paper - it’s light and pretty fun (as far as I remember anyway). A bit simple but might be enough to spend some time on.