If what I'm experiencing is working as intended, then I guess that means tyre wear info in Sidekick is completely useless (at least with some tyre/car combinations and you'd need to figure out yourself those that actually provide reasonable info) and there's no point using it as you're much better off using the Kunos app, as it has the tyre wear bar that gives you at least *some* usable info.
(Nothing against Sidekick if it really is so, it's just that I had no idea and also that it seemed to me like it used to work as expected before. I absolutely understand there might be limitations to the data that are available to third party apps that simply can't be worked around or don't have a reasonable solution.)
To me the Sidekick tire information provided works beautifully in races long enough to actually run through an entire tire life.
In the beginning while the tires are cold I have SK usually set to show pressure delta from ideal as it gives me an input at a fast glance if tires are already on expected pressure or not.
Then I will switch over to the tire temp values and keep them at that to actively manage my tires during the race (adjust brake balance, change driving stile, cornering, brake points, etc …), to make sure to use the tires as equal on all four corners as I can to keep them lasting long with consistent lap times, then towards the end of the tire life (or for trouble shooting a strange car behavior during the race) I switch over to the tire wear indicator and just see for a moment how the tires are doing - only to switch back immediately to the tire temp display to continue taking care of the tires.
The Kunos tire app (and any other tire app available) for some strange reason always has halved my FPS (into underivable frame rates).
Sidekick is always VERY gentle on the frame rates (it costs me perhaps 3-4 FPS) and only the recent hiccup I have seen at a single track (Monza) has taught me how much I really depend now on Sidekick (couldn't race without it anymore).