Here is the stat stability chart from fangraphs: https://library.fangraphs.com/principles/sample-size/
“Stabilization” Points for Offense Statistics:
60 PA: Strikeout rate
120 PA: Walk rate
240 PA: HBP rate
290 PA: Single rate
1610 PA: XBH rate
170 PA: HR rate
910 AB: AVG
460 PA: OBP
320 AB: SLG
160 AB: ISO
80 BIP: GB rate
80 BIP: FB rate
600 BIP: LD rate
50 FBs: HR per FB
820 BIP: BABIP
As it stands right now, McGonigle has 185 PAs, 151 ABs, and 119 BIP in AA. So his BB%, K%, HR rate are all useful, and ISO is 9 AB away. We basically need to have 6X more ABs before BA has any meaning and 6.9X more BIP before BABIP would have any use.
There is also the stats that correlate most to MLB performance: https://medium.com/the-sports-scientist/minor-league-stat-stickiness-hitters-cbb694a11282
Hint, it's K% and BB%, followed by home run rate.
It's really simple, given the small sample sizes here, there are only a few stats that have any value in looking at, and those are all the stats that McGonigle is absolutely elite in.
Comparing McGonigle in A vs AA:
BB%: 13.5 vs 16.8%
K%: 11.2% vs 11.9%
ISO: .277 vs .278
HR rate: 1 per 20.71 ABs vs 1 per 15.1 ABs
McGonigle's performance in AA is superior to his performance in A ball when looking at the stats that have actually reached stability and have some use, and those stats are also the stats that are most relevant to look at when projecting forward. BA and BABIP will never have a sample size large enough in the minors because it takes almost 2 whole seasons worth of data to have any use whatsoever.
McGonigle is not being challenged in AA, and he won't be challenged in AAA either. The jump from AA to AAA is not that big for somebody who is so far ahead of the AA level that he's posting numbers like this. There is no question that McGonigle is too good for minor league pitching, the only question is how he will handle to the jump to the majors. There's only one way to find that out, and we will find that out shortly, not a year from now.