Yes, there are many variables involved in getting a good shot. If you are experimenting I think it’s important to change only one of them at a time, otherwise you won’t know which of them has contributed to any difference.
I have a simple flat 9bar profile for setting-up (dialling-in). I use my pre-infusion stage first, to the first drips, then time for 36g out from 18g in and aim for around 30sec for that. Pre-infusions take up to 20sec, usually less. If I didn’t separate them from the main ‘pull’, I wouldn’t know when the second stage actually begins.
As for steaming, lowering the pressure may help because things don’t happen so fast, but it may be a matter of technique. I find high pressures useful for getting the job done faster. Try doing it completely wrong, with the tip too low and then repeat in stages, raising it until you start to get the right result. I still don’t get ‘perfect’ microfoam but it’s much better and more reliable than when I first started.