When we say “don’t do things in Tick(),” we mean “don’t implement the Tick event in blueprints, and don’t set the actor-ticks flag in C++.”
If your blueprints don’t actually implement anything on Tick(), then there’s nothing for you to remove.
If that is the case, then perhaps what you’re trying to do is more work than the current systems can do as-implemented, and you need to build better systems (presumably in C++.)
The pathfinding and RVO that’s implemented in Unreal Engine is mainly for sparsely populated NPCs, not for full divisions of RTS units. Think “Skyrim” not “Age of Empires.” Path finding is generally one of the main challenges of building good RTS game engines, so it wouldn’t surprise me if the default behaviors in Unreal just aren’t up to that particular task.
Maybe there’s still something going on in your code that you could fix, but it’s hard to tell from just a forum conversation – you’d probably need to pair up with an experienced developer to debug it for real.