I think, if done right, dogs are massively beneficial to children.
Our dogs have been really good formy dc’s mental health. My eldest (now 19) has ASD and it was noted by his assessors and therapists that, being able to sit quietly with the dogs massively benefits his mental health, by allowing him to just ‘be’ and destress from the day. It has been repeatedly mentioned in various assessments and reports since he was 8 years old.
My other ds 9 (now 17) has become very ill over the last few years. He has been stuck at home since he was 14 years old and is still pretty much housebound (even more since Covid, as he is CV, but too young to eligible for a vaccine). He and our remaining dog have been best friends ever since they were tiny (he was 18 months old when this dog arrived as an unexpected, unplanned rescue pup) and having the dog at home with him has been a sanity saver, giving him something/someone else to focus on and on good days, being actively involved in his care keeps him mobile and gives him a routine to break up the day. Also, with the dog always being here, he hasn’t felt as isolated as he could have done.
My dd is 12 and dog mad. Dog walks were a lifesaver during lockdown and having a dog also helped her transition to secondary school mid panemic, having found and made friends with a group of similarly dog mad friends at her new school.
Having said all that, I do feel strongly that you must actively want a dog yourself for it to work out. They are a lot of work, a huge commitment and even an easy dog will drastically change your lifestyle, in terms of spontaneity. Also, with the best will in the world, even with dcs who are actively interested and involved in the day to day care, the lion’s share will always be down to you and ultimately, given for example my current dog, who is almost 16, you will most likely be the one left to care for them when they are elderly and high needs, when your dc moves on to uni or employment. It has to be a whole family decision, with everyone in agreement that they want it and will be actively involved.