Hi @AnnieNew ,
I can relate very strongly to this post! I am also the parent of a very bright, loving but spirited 4 year old - it can definitely be incredibly challenging sometimes! ReachOut is aimed mainly at parents of young people aged 12-18, so this forum may not be the best place to hear form other parents of young children I'm sorry - but I'm sure a lot of parents here would be able to remember the challenges of trips out with young children!
One thing I've noticed about my son is that he can really struggle with transitioning from one activity to the next, which sometimes results in a lot of defiant behaviour around getting dressed/ meal times etc. Giving him an idea of what we will be doing, and when, has been really helpful with this - talking to him about expectations and consequences before we do an activity also seems to help (sometimes!).
One resource that I've found really helpful is the Raising Children's Network, they have some great materials on typical preschooler behaviour and different strategies that may be helpful- I've linked to some of them here.
I've also found Janet Landsbury to be a really great resource who talks about toddler and preschooler behaviour in a really respectful, gentle and evidence based way, are you familiar with her writing at all? It sounds like her approach may align with your values as a parent, here's a link to some of her writing about challenging behaviour if you find it helpful.
I'm also wondering if you've ever discussed your concerns about your son's behaviour with your famliy doctor at all? It looks like you're outside Australia, so I'm not completely sure on what resources are available in your country, but we also have early childhood centres in Australia which are a free service for parents to talk to health care professionals about their children's development up until school age - they can be a great place to get some more support, and also get advice about whether it might be helpful to have your child seen by another health care professional like a speech pathologist, OT or child psychologist, to see if there's any underlying issues that might be causing the behaviour.
Wishing you all the best - parenting small children can be incredibly demanding, and it's clear that you are an engaged and loving parent who wants the best for your kids I'm also wondering if you have any support from family and friends when you need downtime? It can be easy to forget as parents but looking after ourselves is also incredibly important.