It sounds like you have a strong idea of how big a slice of the player’s experience should consist of combat. Different mechanics will take different amounts of time to play through, and require different levels of involvement.
In Kerkerkruip, the player is fighting stuff all the time. The ATTACK combat system gives the player a lot of options, and understanding those options takes some work. That’s not a problem, because mastering the combat system is the game. (Not all of Kerkerkruip’s combat complexity is inherent to the underlying ATTACK paradigm but whatever.) We can imagine a non-combat-focused game that brings in all those rules for the purposes of just a few isolated combat encounters: Those encounters might have the potential to be tactically engrossing, but for players who don’t know the system ahead of time it would be difficult and annoying!
I wrote a combat system called “Ryan Veeder’s Perfect Combat” that I used in the middle of Winter Storm Draco and the end of The Roscovian Palladium. It’s a few steps beyond “attack [foo]” but it’s still really simple—I wouldn’t call it “tactical” probably. But I wanted to enable a halfway-interesting combat scene without forcing the player to learn a complex ruleset. I honestly don’t know how long a Perfect Combat battle feels to the player, though. I worry that they take too much time to figure out.
Including scattered combat encounters in an exploration-based game sounds like a tough trick to pull off, because, if the combat mechanics are appreciably complex, you want to work your way up from simple/easy encounters before asking the player to demonstrate mastery of the system—which you can only do by restricting the exploratory aspect. Not an impossible task, but certainly not a trivial one!