I sometimes wonder if people on mn have ever read anything else on mn.
I mean this r thing comes up EVER SINGLE TIME anyone asks about pronunciation.
Most of the time I feel sure people are doing it just to make a point.
So, we all know, there are 2 A sounds. Let's just call them a long A (as in carpet - whether or not you say the rrr, it is still a long A) and a short A sound as in caravan - again, doesn't matter how you say the r)
Reception age children can understand long A and short A.
It is pretty basic.
So, the actual question was about which pronounciation people use.
There are two, one with long A and one with a short A.
There you go, no need to have a debate about rr at all.