In the past ( a long time ago) you identified your top choice on UCAS and unis could see your other choices. These days neither of these is the case.
All of the very competitive unis will be offering to those who apply to Oxbridge. They know that 3/4 of them won’t get Oxbridge offers. They want strong students. They know that they must over offer, because offer holders also hold other offers and might go to Oxbridge or other top unis instead. And they know some students will miss their offer and they might not then take them.
So, focus on being a strong applicant for the places you are applying to. If you are predicted all A stars you can apply where you like, and for all but the most competing subjects [Econ, CS etc) you may get offers from everywhere. For those extremely popular courses, you might still only get a couple and have to accept that. If you’re a strong applicant but not quite all A stars, for most courses at most places, if your grades are at the standard offer level, you’ll get an offer. It won’t matter when your application goes in. Those who don’t get offers are usually those whose application isn’t so strong, it’s not because if the timing of their application.
The advice of something aspirational (could be Oxbridge for some) and some that are achievable and something as a back-up is a good idea. Know that for the very competing courses at the top places, that even candidates with top grades and impressive PS don’t all get offers as there are just too many of them. But also know that most courses aren’t like this and if you have the right grades, you’ll get offers. And also that, even if you’re a near-miss come results day, many many places will still take you, but you can’t be absolutely certain on an individual course basis until results day itself.
Lower offers for applicants much stronger than the usual, as a recruiting tool, or offers where the grade drops if you firm, tend to be used by the not so selective unis, that really need to draw people in. Top courses at top places tend not to do these things - they don’t need to.