I have not owned dogs because I knew I would be travelling and living abroad and thought it would not be fair to have a dog and then leave it behind. But many of my family did have both dogs and cats and my granny who had a farm, was well known to be very good with dogs and not only had her own ones but would be asked advice by people on their animals and the police would sometimes bring her a dog to look after etc etc., so have been round them all my life.
As you say there are far more dogs around since covid. The problem is that people have got an animal in that time, but have not been able to meet other dog owners and socialize etc and learn by good example how they should be treating their dogs or meeting others with or without a dog.
Fortunately (or unfortunately depending who you are ) I have been a teacher and head of various departments and an eldest, so I mind my own business normally but where I see a problem I speak out. Firstly as others say it is not the dogs but their owners , who really need training. I go to Cafe Nero locally where dogs are allowed and the great majority of dogs and dog owners are very well behaved, so dogs are sat quietly and out of the way of people and staff passing tables. However one day I was there and there was a young women talking to a friend across the table and her small terrier type dog was constantly barking and making a noise. Other dogs who were usually fine were getting restless and you could hardly hear yourself speak if you were in a table close to her. She took no notice at all of the dog, simply ignoring it and talking to her friend. I went across and asked her to take her dog outside, calm it down and then bring it back in. I deliberately stood a little closer to her than you would normally, did not blink and just remained there quietly waiting for an answer. She obviously found that a bit intimidating, glanced round and saw many people looking at her , and muttered oh sorry, took the dog out and did as I suggested, and came back in with a quieter dog. I said thankyou and returned to my seat.
On another occasion I saw a woman pour some tea or coffee into a saucer and prepare to put it on the floor for her dog to use. I immediately said "Please do not put something a human uses for your dog to use. They have dog bowls for water if you want here. She replied that it wouldnt do any harm and it would be being washed up anyway. I told her that if she did use it I would speak to the staff and complain. That what she did in her home was her concern but that in a public place , especially where there were water bowls available for dogs , she should not do it. She huffed but at least did not carry on but got a dog bowl. I said that it was not fair for her to do such a thing as other people might not say anything but may not come back to the cafe if they saw such behaviour.
The worst things I find is not in cafes but the wretched owners who have their dogs on long leads and dont check where they are or shorten them in busy streets etc. I have complained to one local man who wanders down the high street looking in shop windows with no idea where his dog is or checking for the safety of people passing.
I might say that in the cafes etc I have also spoken to noisy children running about too. But I have a couple of tricks that I can do with my hands and also am quite good at making paper ships and aeroplanes ,so can often get them interested in doing something more interesting. When my son was very young I always chose a seat where he was unable to get out without passing me, and usually had a small book or pad with crayons with me to give him something to do. We are not good in this country about taking children out to restaurants, and they then do not learn how to socialise and enjoy meals out. When I lived abroad there was no problem with children being there. Normally they would get a small portion of whatever food was on offer and not be offered the appalling diet of fish fingers or beef burgers etc . so learnt to try many things, and meet lots of people of all ages.
I have occasionally had snappy comments back from dog owners or parents, but in the majority of cases things have improved after I have spoken to people and sometimes they genuinely dont seem to have noticed the effect their pets or children have had on others. I always thank them if they respond sensibly and intend to carry on speaking out when I feel it is necessary.
The cafe owners are in a difficult situation re dogs or no dogs, if they do not have a big enough area to be able to separate the groups and in this difficult time obviously do not want to turn customers away, but yet they will lose customers , when those who do not like dogs or at least dont want dogs disturbing them in the cafe, and it is the responsibilty of the dog owners to be aware of the owners situation and behave in a decent way, and think of others and not just what and how suits them. Just generally trying to look at situations from others point of view instead of just being totally selfish and only concerning yourself with what suits you, is not a lot to ask and there will usually be a middle way if we look for it that everyone can be accommodated if we try