I think it's not even the behaviours that you recognise, is it? It's the utterly exhausted, drawn out, despairing tone of a parent who has given it their all and their all has not worked and now they are heading into a very dark place mentally with all kinds of worst fears looming on the horizon.
It's a bit like on Relationships threads when someone will post an utterly bizarre scenario and people seem to "jump straight to" saying the partner is abusive and OP should LTB.
It's not what they are saying, it's the bits between the lines, a kind of vibe.
Something which frustrated me for a while was looking back at old advice I'd had on threads (with parenting) with both DS1 and DS2 and recalling that people had reassured me it was normal, they would grow out of it etc.
The thing is that an occasional tantrum at 4/5 when they are exhausted or have had a big disappointment (or both at once) is unpleasant but normal, and you probably don't need to do anything for them to grow out of it. Having constant arguments and tantrums multiple times every single day over every interaction is NOT normal at that age. At two or three, maybe. But not typical at 4/5. Frequency and intensity matters, and how frequently and competently they are using other approaches to the same situation matters.
Behaviour is developmental IME - yes they might copy inappropriate behaviour, but if it sticks then that's showing you the child hasn't learnt better techniques to approach the situation, so they stick to the one thing which they do know how to do, whether or not it works. With typical development, that means you see the annoying/immature behaviours less and less as they assimilate the more effective skills they are learning. But some children don't pick up the preferred skills as easily, so they are left with options which cause them problems and/or are more difficult for adults to deal with.
In any case, you can't force development by shaming/punishing the immature approach, that might work in the case that they are already proficient at using alternatives, but it won't work well if they are struggling with the more mature approach and it definitely won't work if they don't HAVE the skills to perform the more mature way. Working on the skills will help, but most parents are not child development experts and don't necessarily know how to get there from where their child is now. Speaking to a professional might help if you can get the time with them, and should be done anyway to rule out things like hearing problems, or something like an allergy which might cause stomach pain or congestion. Other than this you're mostly left in the dark, which is frustrating.