Interesting stats. I worked out mine to about 1.4 hours per day. However, until mid March this year my GT Sport driving was mostly grinding credits and mileage, and I barely ran any FIA races until then. So the actual number is a lot lower. On average since March I estimate I probably ran about 1 hour of practice time a day for the FIA and dailies.
I think I'm weird in that I reach my peak laptime very quickly and practicing too much is actually making me slower. Even in daily races I usually set my fastest time on Monday or Tuesday within 5 laps or so, and then just plateau for the whole week. Unless it's a new car/track combo, my mind just gets bored too quickly to maintain enough motivation to push for that last few tenths. I guess that's why I can't be an alien
I find that the more laps you spend unable to beat your previous best, the more and more nervous you become and you start missing braking points, apexes, etc. In fact from previous GT Academy where you can have up to a month to set a time, I find overpracticing can lead to burnout very quickly and your performance just spirals down from there.
For the FIA races because of fuel & tyre wear I stopped practicing in time trials altogether and just run race simulations in lobby now. Previously with extreme tyre wear I do 2-3 race simulations with different tyre combos, but now with much lower multipliers I just do 1 run and be done in 20 minutes. In real life you don't have unlimited practice time, so that's how I approach these races. I wonder how aliens spend their practice time. Do you guys just run hotlaps in time trial, practice alone in lobby or do races with other aliens?
Amazingly, from Jason Guernsey's site there's someone who's done over 10,000 Sport mode races
I wonder how many hours he/she plays a day
https://www.jasonguernsey.net/gts/drivers-by/race-count