Usually HVAC heat exchangers pretty close to an exterior wall, because the run to the exterior heat exchanger is ideally not too long, so you can tap into the return plenum there. But even if there’s not, there’s some flexibility in where you tap in (though some places might be more ideal than others).

For us, it was just a couple 6”holes in the cinderblocks of a basement wall (at least 6 feet apart).

We did this for our house built in 68.

Obviously it depends on the architecture but we where able to place the central unit beneath the roof. All rooms on the first floor are connected through the roof space. A central column runs through the first floor and goes to the corridor on the ground floor. From there we where able to connect all rooms. The floor lost 15 cm height but it has 250 cm so it did not matter much.

If you cannot do it you can run the pipes on the exterior walls and insulate them with ,20 cm Styropor.

Using old obsolete way oversized chimney. Enough place for pipes and cables.

Laundry chutes too

I planned out ceiling suspended pipes in only corridors, where I figured the visual annoyance is least. 2 years in, I don't regret it at all.