First, what you call that: The navigation buttons. Here is the property of the form that lets you turn that feature on or off. Note that for unbound forms there is nothing to navigate and you might therefore not see them anyway on special unbound forms that do their own navigation. I.e. there might be nothing to turn off for an unbound form.
Office VBA reference topic
learn.microsoft.com
Second, you can't easily enlarge it. A lot of articles look like they respond to a search for "Resize navigation buttons" but they all (so far as I have found) seem to be resizing the navigation bar, which is a totally different thing.
Third, yes you can "roll your own" version of the navigation buttons and disable the standard set. Your operations would then involve some interaction between your custom buttons and Me.Recordset and/or Me.RecordsetClone using the Me.Recordset.MoveFirst, .MoveLast, .MoveNext, .MovePrevious, and .FindFirst or .FindNext operations. Some extra safety could be assured for the search options if you do some of that manipulation using Me.RecordsetClone and then copy Me.RecordsetClone.Bookmark to Me.Recordset.Bookmark if your search succeeds.
There is also the issue that "rolling your own" can get your form confused. For instance, a .Requery could make the form momentarily act as though it were unbound. See this link regarding .Recordset operations which includes remedies for that case.
Office VBA reference topic
learn.microsoft.com
See also this video by Daniel Pineault, who is a recognized expert in Access issues. He produced a directly applicable video on the subject.