I’d try to print the model without support (it’s flat on one side, isn’t it?).
In my opinion there is not too much wrong with your machine, since the support comes out nice Have you tried changing the point size of the support? It looks like your support cannot hold the model well, maybe because your point size is relatively small?
I’m not suggesting that there is not enough support, but that the contact point of the supports are too small to hold the model. Could you share a screenshot of your support settings?
We’re using z-vat 3rd party vats which have silicon coated glass bottoms, but the plastic vats are recoatable too, have a look at the DruckWege ReCoat kits
That is a worn-out tank right there I’m afraid. Did you print the model in the same position several times? Looks like the area corresponding to the support points has suffered burn-in. You need to try to avoid printing over the same position as much as possible, and in general the tough resin seems harder on the tanks than other resins in our experience, which is why we got the recoatable z-vat glass tanks
I had the silicone layer in a tank that I had used for a short time delaminate from the tank. It allowed resin to seep between the silicone layer and the tank. I could not get anything to build at all. The cured resin beneath the silicone absorbed enough of the laser energy to prevent curing. The tank looked clean and smooth just nothing would build. Had to replace the tank. My guess is the same thing would happen if the resin got on the outside of the tank. Just wiping it off might not be enough to restore transmittance. If you clean it with alcohol just be sure to use virgin alcohol right from the bottle not contaminated with resin from the rinse tank.