And then instead of one problem, you have half a dozen or more problems.

Currently, the problem is somewhat simple:

Attach to Node 2 forward, and be able to produce 47m/s of delta-v attacked to a station of 450 tons.

Boost-de-boost maneuvers of the whole station are well researched at this point, so we know the force vectors and what happens to the station when doing so. The station itself can also help with attitude control.

If you break it up in pieces, you would need to find out where to attach, what the force vectors need to be to properly boost of module through its CoM without spinning out of control. Most pieces won't be able to support the burn with attitude control.

You'd also have to disassemble the station, which in itself might take months or longer. All while diminishing the capabilities of the station further and further while doing so.

Honestly, keeping it as one piece looks a lot simpler. You basically just need to do a stronger de-boost burn. So basically business as usual, just more fuel.