DS1 has always been good at playing on his own for periods of time which is great as allowed me to do 1 small task at a time. Eg dishes, stacking or unstacking dishwasher, shower, washing etc. Even now at 21 months he is good, I have friends whos kids need played with all the time and can do nothing, yes DS1 has days like this but few and far between.

DS2 I can put on the floor alone and he loves it while I do something with DS1 like change him or bath him etc.

As long as you do interact with them at regular intevals during the day thats fine.