Octopi (PI4) for UART passthrough to connect Marlin and TFT35?

This is not an issue per se but rather an idea.

Basically I have an Ender 3 pro with SKR mini E3 V2.0 motherboard on Marlin, a Bigtree TFT35 E3 V2.0 screen and Raspberry PI 4 running Octoprint.

Right now I am using the following setup:

Pi4 --> Marlin (via USB)
TFT35 --> Marlin (via TFT pins on motherboard)

The setup works fine except for I'd like to: 1) eliminate USB connection; 2) Continue to use TFT35 with touch mode and ideally let Octopi talk to TFT35 to sync status.

I came across this thread on github: https://github.com/bigtreetech/BIGTREETECH-TouchScreenFirmware/issues/281, which proposes a solution to connect PI->TFT->Marlin. The solution solves my problem but apparently there are some lagging issues as TFT is in the middle handling the Pi <-> Marlin traffic.

Given that PI4 has 5 PL011 UARTs, I am wondering if it is possible to have Marlin<->Pi<->TFT passthrough. Is this physically feasible? It looks like hooking two UARTs on Pi and forward signals is possible but I would assume there are more than that (e.g., what if Pi and TFT talks to Marlin in the same time).

I just like to ask around and see anyone has some insight on the feasibility of this idea.

It is far past my abilities to achieve something like this but it doesn't seem to me like it would be impossible given the know-how.
It would be very handy to have the tft 35 or equivalent be able to have a 3rd mode along with the touch screen and marlin mode which acts as an octoprint mode.

Some one has to do this at some point right?