Nope. Don’t do it - I went to sleep after race 2. I completed the following 3 the next morning, got the Carrera GT, then it wouldn’t go back to main menu. After reboot, I had to do the entire championship from the start. And to make it worse - I then got different car instead, which I didn’t care for!
I play across PlayStation 4 and 5. I often sleep my 5 at the beginning of race 3 and then go do race 3 on my 4. It's pretty seamless. You can't do anything else in GT but you can do anything else and just resume from the start of the current race.