Because we are a really small team, we drive against AI too (online). And yes sometimes it can be frustrating to drive against AI.
If you know that the AI drives stubbornly on the racing line, then you have to take that into account if you want to drive with it. On the other hand, the AI also drives quite conservatively when it gets into trouble (risk of getting onto the grass).
Here you cann see a stream of a race with another team driver and 5 AIs.
https://www.youtube.com/watch?v=ierJqCDCHaQ
My teammate struggles with the AI more than I do.
And because we're driving against the AI, we allow car resets while racing. That can reduce frustration while racing.
The behavior of the AI is said to have changed/improved in the future, new version. Let's see what happens.