What should we not miss out on in South Korea?

We are a couple in mid-30’s, travelling with a baby for the first time to South Korea. We will have cca 1 week in Pohang and then 5 days in Seul. Baby is 10 months old. Which places and experiences should we not miss out on, in your experience? Many things I find online are just not realistic for us to do with a baby - or so I presume..? Thanks in advance for all the recommendations:)