How little can one train and still be competitive?

I'm a Masters, Cat 4 (was once a 2 and a fairly high level junior, but have since greatly downgraded).

I've ridden 100,000s of miles in my life and am pretty burned out on long miles. What I am still good at is suffering and intensity, and I'm also getting back to my old racing weight of around 83kg. I trail run in the winter and start hitting the group training races in March. I hit the gym at least twice per week.

I guess my question is--what is the lowest possible average hours per week on the bike that folks on here do and still remain competitive in crits or shorter gravel/road races? What works for you?

At the most, I'm only interested in the group training race on Tuesdays and maybe one more slightly longer ride during the week. This will be max--3-4 hours per week with one trail run and two gym sessions added in. Have any of you successfully executed such low bike time?

Edit: and I will say that including gym work, a trail run plus the bike time, I'm training at least 6 hours per week. But just 3.5 or so on the bike.