As far as oil leaks go, I finally got mine where there are no drops of oil on the driveway and oil pan is dry. I had to do the valve cover gaskets at about 8 years after truck purchase (bought new) and it only stopped the leaks for a few years. The problem is that the shop manual is a bit lacking in that it does not address the cam plugs and I more or less verified that is where the oil leak is using a mirror. It's difficult to criticize Toyota, but in the case of the cam plugs I do. They are metal plugs like freeze plugs with a very, very light coating of rubber. They simply won't seal for long.
One popular youtuber says don't put FIPG on them because Toyota does not but some say you should and I agree. Also, follow the dirs for FIPG, clean all surfaces with brake cleaner to remove oil and don't start engine for 8 hrs. Warning though - it appears some have pulled out the head threads on the cam plug clamps when removing the bolts. I also torque the valve cover bolts twice because the gasket compresses and torque goes to zero after first torque.
Other leak source is the oil cooler. This is actually easy as you can remove it (one bolt, two water hoses) through the wheel well. You have to put some grease on the o-ring so it does not fall out.
When you change the timing belt be sure to change crank seal and cam seals. My crank seal was leaking last timing belt change.
Lastly, change the oil filler cap gasket. I did all the above and oil drops started again and I was really scratching my head until I isolated to the oil filler cap. I guess the blow by will force oil out if gasket has failed.