When your child is young, such as 6-8, they need a lot of exposure to chess to gain experience quickly, and they have time at that age. People learn chess by making mistakes. The more mistakes s/he makes, the quicker s/he learns. Understanding rules or theory is not enough. S/he needs real game experience. If your child only plays one or two games a week, it will take her/him at least 5 more times to progress as a child who plays 5 games a day.
5 games a day takes about 1 hour. One or two games might be longer, but most are short. If you say that you don't have 1 hour to spare, then you should lower your expectation and just let your child have some fun.
It's not easy to ask a child to play 5 games a day, especially when s/he has other toys to play. It takes a little bit of strategy and persistence. I initially asked my son to play 10 games a day. He executed for a few days, then start to rebel. He just procrastinated playing until bedtime. So we reduced the requirement to 5 games a day. But soon he procrastinated again and began to strike. And he didn't want to play because he had lost too much. Everyday we just nudged him to play a few games. Sometimes he did, but sometimes he just didn't want to play. But we never gave up. Recently he started to win more again, and he became happy to play. Now it's much easier to tell him to play 5 games.