The "lockdown puppies" are only now starting to drip into rescue centres, now when they're no longer puppies but teenage dogs with a range of behaviour issues including separation anxiety and, as someone mentioned, no longer kid-safe as they are DONE with that chaos.
I do know of one rescue dog from a big rescue who was handed back after several years in their adopted home, because, after a few years of being fine with kids, suddenly have kids at home during lockdown 24/7 led the dog to turn into an anxious mess, clearly worried, not ever relaxing, poor thing just couldn't cope and couldn't rest and there was a risk of that escalating. He needed a quieter home.
Demand for dogs has just been insane over the last year. Rescues, big and small, have been frantic, especially larger ones who had staff on furlough and no volunteers and smaller ones who couldn't have volunteers on site either. And they have been getting HUNDREDS of applications for dogs every.single.day. But out of all those hundreds, only a handful are going to suitable for each of their dogs.
It's no use getting angry with the poor rescues who are doing their best. Their priority is finding the perfect home for each of their dogs. It's not their job to find you a dog. There's a lot of entitled people sending a constant barrage of of complaints to rescues who are having a hard enough time as it is.