@nyev maybe a picture of the optional phono card?
It looks like it has 2 inputs that are balanced, so I would be using a balanced IC as opposed to RCAs.
Which means that the TT should have balanced connectors.
I have one tone arm that has a DIN to RCA, and another that terminates into a block that houses the XLRs.
I have ALL of my devices going through one Torus RM-20 isolation transformer, which, if it matters, has a ground terminal (my Diablo amp also has a ground terminal).
I would be having the ground from the TT tied directly to the integrated.
That could be either via and XLR shield… or via the shield wires of RCAs, where the RCAs carry the +/- at the tone arm end, and the chassis ground is tied to the RCA cable shield.
Then on the preamp/integrated side those shield wires are both tied there.
I just made up some a couple of weeks ago which are XLR on the TT side and RCA for the phono amp side. The shield wires on the phone side are long and exit before the RCA to be tied to the phono amp ground tab.
Which TT are you considering?
Galibier Design in Colorado makes cables and nice TTs, and is pretty pleasant to talk with. I would just outsource your cable to Tom directly, and not overthink it.
It’ll probably be between $500-1k$ for a custom cable, but it will be likely be optimal.
The other advice I got from (Mark) Dohmann was to go to bigger ga as quickly as possible… So rather than use a long 30ga Linz all the way out to the phono stage, have the tonearm cable short and then move to a 20-23 ga to get the last 3/4 m.