Ours worked on some local cats, and drastically reduced the shit in the garden, but they took to using our shed roof instead, which ad you might imagine, smells lovely in the sunshine
Prickly plants ro not work on the lawn, garlic pellets did work until it rained, but rendered ds all garlicy too. Cat repelling spikes worked really well for a.few.weeks.
This year I am going to try prikka strips on their main routes into the garden, and put netting on the lawn over night, because it is ridiulous in our garden.
Over winter, they somehow ripped up netting I had over the veg plot, and have been using it as a litter tray, so I am loathe to grow veg there this year. They dug up spikes and pottery shards I'd put in, and shat around them. I am so so sick of the disgusting creatures!