First up, just accepting that I'm not not going to be perfect and there are going to be times when I take the easy way out (like this morning when I just stuck the TV on for them while I got things done). No one is perfect and most kids do fine. Expecting to be perfect is like people who crash out of a diet after one day where they fail to stick to it. Be kind to yourself. Do what you can when you can. Sometimes I will have the time and energy to go all deep and meaningful with my kids, and sometimes it's just a quick "stop hitting your sister or I'm selling your trainset".
Secondly, when I do make the most of the good times, it tends to pay off later. It's like taking the hit when we did sleep training with my youngest. It was hard work for a couple of days, but the end result was totally worth it. Same goes for stuff like this, sometimes you just get a breakthrough when the kid "gets it" and from then on they are just a little easier.
Finally, sometimes I'm going to be grumpy, stressed or tired (probably at the same time), and I'm going to snap, or lose my temper a bit from time to time, like most normal people. But I then make a point of saying "I'm sorry I didn't mean to snap at you, I'm just very tired/stressed". I've found my 4yo is pretty receptive to that, he gets it. It's good for kids to see you owning up to your own mistakes and understanding why. Recognising you've done something wrong, owning it, and apologising is a really important skill for kids. So much of the crap in the world is caused by people just not being prepared to accept when they are wrong and owning their mistakes and failures, but doubling down and digging in.
In short, don't take all these "perfect partent" stories too much to heart, most of them make them seem more straight-forward and perfect than they really are (and there is a smell of "look at the mystical native" about a lot of them that I think clouds the narative). But there are often good things to learn from them. Every kid is different so having a wider set of ideas to try is always great.
Parenting is always a series of trade offs. On one hand maybe I am not teaching him how to self regulate and go to sleep. On the other he gets an extra hour of sleep. The reality is there is probably a better solution that I haven’t thought of but there is only so much time to research and explore each little issue that comes along!
I only recently figured out how to phrase it, you can be "firm" without being "strict". You don't have to be a shouty monster to have limits, boundaries or firm ideas over what is acceptable behaviour. Kids seem to like consistency, they like knowing what's what, that doesn't mean you have to be horrible about it.
We're all making this stuff up as we go along, and every child and situation is different though, so you've got to go with what works for your kids.
My practice is to reflect on when things like this happen. We have one 3yo son but issues do arise where we get upset, and reflecting on them and preparing myself for the next time helps me address what he needs to not do whatever it is that upset me, and for me to not get upset which makes him upset.
I guess it's not so strange now but when I started parenting I figured my parents' approach would be best, like expecting kids to do their work because it's basically their job.
What I didn't expect is how powerful the word "please" is.
Seriously, I'd been trying to get him to do small tasks when he was about two and understanding us, but wouldn't ever, EVER do it. I'd talked with a teacher who mentioned her class listens to her because she asks them politely and other teachers who don't have unruly classes. And so I finally caved and said "...can you please put your dishes in the sink?"
The difference was night and day. Immediately, he picked up his dishes and put them in the sink. Since then, I think we've done an OK job of inviting him to be involved in chores and tasks because anytime he realizes we're working on something the first thing he says is "can I help you?"
Anyway, point is you can learn so much just by paying attention, mindful reflection, careful preparation, and some study mixed in there. And as someone else said, having the humility to acknowledge to your kids' face that you were wrong goes a long way.