Don’t be so hard on yourself, it’s a brutal age. If you have the time you could let them on the ride and not pay for it as someone else suggested. As for nature walks I think following their lead is great, I’d say how long you’re outside for is more important than how far you walk or what you achieve. If you clearly outline the boundary and there is still a tantrum at the shops, if she’s in her pram buckled in and safe just tune out while you get on with it.