This and the few years after was the golden age for me - single parent, dc with 3y3m age gap and it was while they still got on a small amount of the time, before all the bickering started. They are teenagers now and it’s hell going anywhere with both of them. For me I often did what I fancied and kids tagged along as a pp has said, or suited the older and the little one tags along. What I did still do was use a buggy at that age. Dd2 could get in if tired of walking on longer trips and at least it was somewhere to put all the stuff even if the dc never got in it.
Picnics - what do you mean they don’t eat picnics? don’t like sandwiches? Neither do mine, I’d bring rice cakes, chicken goujons, breadsticks or toasted pitta and hummus to dip, crackers and cheese, tub of leftover pesto pasta etc. Or do they not eat outside? (Could probably be solved by sitting and eating with dd5 and ignoring protests)
Trips to ikea are one of the things that have stood the test of time and we still love now - super cheap breakfast/lunch. Long wander round, super cheap ice cream on the way out - never gets old 😆.
Lazy mornings can be filled with some pre prepped snacks and some tv- absolutely not a problem
soft play has its place but agree annual passes for localish attractions are great and mean you can pop to the zoo/farm/play centre for a couple of hours and a packed (not picnic) lunch rather than feel the need to make it a big all day outing. I do struggle to understand people who talk about it being so hard/being in the trenches etc (and my youngest was a nightmare 😅)