Advanced trainee, trying to lose 10g.

As the title implies, I am in the advanced strength numbers regarding my lifts. I weigh 100kg and am 185cm height with BW press, 140kg bench, 170kg squat and 240kg deadlift. My question regarding training is should I try progressing on a deficit with a really tryhard program or just reduce my frequency from 4x/week (upper/lower split) to x3 fullbody to have more free time but still get just enough practice to keep mass and strength loss at a minimum? Is bringing up small muscle groups size-wise such as the biceps with isolation exercises out of the question during my 10kg weight loss journey or just stick to compound exercises?

I see no reason why you couldn’t progress strength-wise on a small deficit if the programming is appropriate for you. I don’t know that I would spend extra training time doing more accessory work, but Strength II or Powerbuilding II would be a good program here.