OK. This forum is mostly about garden building - paving, sheds, fixing your mower, etc. The “gardening” questions are mostly about how to cut things down. (OK, maybe I’m being unfair. But there are certainly more builders on here than gardeners.)
Wild flowers can be surprisingly difficult to grow. The ones that like your particular conditions may be what you think of as weeds….
At this time of year, it’s easy to get a quick burst of colour by buying small plants, filling an improvised planter with them, and watching them grow through the summer. The most expensive thing is probably the compost to plant them in.
For relaxation, get bird feeders and improvise a bird bath.