What no one seems to say is: these are the things you might be able to do something about, and these are the things where you just have to grit your teeth and wait for the baby to sort it out.
A lot of the lessons needed in early parenting really can only be learnt through experience, rather than through advice. This is especially true for sleeping.
Plus it is natural for all parents to think their way of doing things is the right way, or their longer term goals for how they want to parent are the ideal and perfect way to parent their child. Of course everyone thinks this because if they thought doing something different for their baby was better then they would be doing that. That doesn't mean that everyone else's way is wrong, just different.
So that makes advise hard to give. You'll find lots of you could do this, have you tried that, but no do this and it will work because anyone who does that gets slated.
I was on a sleep thread a few weeks back and someone asked what a sleep consultant would say to the parent of a 5 day old baby. In my argument that you don't need to pay for advise, there is lots on MN for free, I gave a post that was effectively if I was sleep consultant to a 5 day old these would be the instructions I would give to the parent. I got absolutely slated from every angle for suggesting a set of instructions to a parent. I do get why, a parent needs to learn and reach their own conclusions about what works by doing rather than being told.
You can do things to 'solve' or help with most routine baby issues. But it either takes a lot of crying or a lot of time and each parents view on how long they will wait and how much heartache they will tolerate is different. So no one really offers an answer to these sorts of questions. What I would do to solve your baby's sleep issues will be different to what you would do. Just like how you would parent my daughter may be different to the way I do. That doesn't make one way right and another way wrong - just means that anyone's advise is only relevant to their way of parenting their own children.