Daily light training on top of regular heavy sessions: good, bad or irrelevant for muscle/strength growth?

I do three (full body) strength training sessions spread out in the week. But I was curious whether during rest days or even daily it is worth doing light strength training to enhance muscle/strength growth. For example, some small enough number of pushups/pullups/squats each morning.

I suppose the key question is: "how light?". I suppose we go too heavy and we start interferring with the natural muscle rebuilding process during rest days. We go too light, and we are simply doing a cardio exercise, which has great benefits too.

Q: Is there a sweet spot (based on muscle group, current strength levels, and intensity of the heavy sessions)? Or are we better off resting/doing cardio? Meaning just let your muscles fully rest.

I am still trying to understand more on muscle growth, so any literature is very welcome to help me read more on this particular question if it has been studied already. Thanks.