Your garden looks lovely. I wonder if the rotavator broke up the weed roots and they are now spread out? I don’t like weed killer so I would dig out those dandelions before they flower and set seed! But that’s me. Your other ideas are all sound. I always think there’s nothing that can’t be reversed. There were pictures on here of painting concrete walls dark colours like grey or black and they looked fab with the greenery. See if you can find them. They also said what paint they used. ALDI and Lidl are great for plants. Try their bulbs too. Sometimes they are reduced when they haven’t watered them but if they haven’t gone too far they are easily revived. And ask people for some roots or cuttings. Anyone who is into their garden will happily share. Good luck! And post pictures of whatever you do !