Well, sorry. It took a while to find the motivation to fix the mod. Turns out it was solvable without unity assets. Although TTS v12.0+ brought problems it came with solutions along (the attachment function)

-The roulette bowl's metal accentuation is attached to the bowl and is one unit (attach function)

-The roulette wheel's metal accentuation is attached to the wheel and is one unit(attach function). The "zero collider" for the metal accentuation should be ghosting through objects, which it didn't anymore due to physics changes in TTS v12.0+. The "zero collider" that was just a cube concentrated to a point was actually having a collider of one vertex. Thus it was interfering and visually detaching itself from the wheel.

-The black "pusher", a physically turning part of the roulette apparatus was colliding with the "red ring", when it didn't before TTS v12.0. The anchor connection for the "pusher" was lifted slightly to mitigate the collisions.

-The roulette ball, black pusher and red ring were re-tuned to accommodate to the new physics engine.

-Roulette ball replaced with a speckled one

Rehosted files.

Changed the colored player mats.

Added scripting:
- ball doesn't jump out of the roulette bowl anymore due to help of scripting
- wheel does rotate automatically when ball is dropped on the red rotating ring

Fix: Part of the roulette table was still selectable.

Relinked files.

- Added payout table texture by Desez2tPunk.
- No more flickering of the player area mats (those with the crowns).
- Accidental unlocking of the table parts not possible anymore! (Thanks to scripting)

Changed friction of the roulette bowl so that the ball moves sooner towards the roulette wheel.

Updated to new Tabletop Simulator 7.0 release. Using now compound collider for the roulette wheel. The wheel is now less smooth and the ball starts to jump a little but it work OK I think.