How much programming is needed to connect the visual, audio
and overall functioning of an average yet high tier game?
It mainly depends on what you define by a “high tier game” and how good are your programming skills, so there is no general answer to your question.
Honestly you can go pretty far with just blueprints. I started with zero code and got movement, UI and basic audio hooked up in a few weeks. C++ only really matters once you need heavy performance or custom systems.
I think the useful way to look at it is: you may not need to write much C++ for a long time, but you do need programming thinking from day one — because Blueprint is programming, just visual.
Variables, branches, functions, events, interfaces and arrays are the same concepts in Blueprint and in code. If you learn them properly in Blueprint, you are not avoiding programming, you are learning it in a form where you can see the flow.
For connecting visuals, audio and gameplay, that is honestly where most of the work is. A footstep is not just a sound: an Anim Notify in the walk cycle fires an event, that event plays the right MetaSound for the surface, spawns a small dust Niagara effect, and maybe tells the character component to adjust speed on that material. A door is the same idea — interaction event, animation, creak sound, then the gameplay state changes so it stays open. Once you understand events driving several systems at once, a lot of game development clicks.
What Blueprint handles well on its own: movement, interaction, UI, inventories, simple AI with Behavior Trees, save games, audio triggers, and most single-player game logic. Where C++ starts to matter is performance-critical systems, very large or replicated multiplayer logic, custom editor tools, and code you want to reuse cleanly across many projects.
My practical advice: make one tiny complete loop first — walk around, pick something up, use it, hear and see a reaction — entirely in Blueprint. That single loop teaches you more about how much programming a real game needs than trying to plan a high-tier game up front.