The ACTI plugin and Assetto Corsa only provides IMO temperature readouts:Hey Guys!
How can i see the tire wear? I / M / O, for tire pressures
Tire wear can only be judged from the single data channel per tire "Tire Rubber Grip".
When you progress through a race you will see that the tire rubber grip will slowly be reduced.
Tire wear in Assetto Corsa is best judged by a combination of inputs WHILE racing.
I very much recommend using the app "Sidekick" to get info about tire pressure, temperature and wear while racing in a very compact and highly focussed app.
Assign the app shortcuts to two buttons on your wheel and you can flip through the tire information (and all other essential information during a race) by the press of a button.
Also essential for judgement of tire life is the app Protires which will provide indicative tire life estimations.
Best of course is to test tires extensively. A well known trick that works great in Assetto Corsa is to run short test sessions of ~10-20 laps at accelerated tire life. This will give you a good feeling how a certain tire will behave (and translate into lap times) towards the end of a stint.