It doesn’t make sense for the Spitfire Mk.22 to have the same BR as the Mk.24.
The comparative advantage of the Spitfire Mk.24 over the P-51-H-5-NA is that it is fitted with powerful Hispano cannons, which justifies keeping its BR at 6.7. Most of the other specifications are similar to those of the P-51-H.
However, the Spitfire Mk.22 lacks the crucial ‘150-octane’ component, and furthermore, its performance is slightly inferior compared to the Mk.24. Therefore, it is questionable whether it is justified for the Mk.22 to have the same BR 6.7 as the Mk.24.
In my opinion, the ideal approach would be to lower the Spitfire Mk.22 to 6.3, as it has a comparative advantage in firepower, even though its airframe performance is slightly inferior to the P-51H.
Your idea has the inherent flaw that the BR of 6.7 for the F 24 was the result of the BR reduction of MiG 15 & Co to 8.0 - and not based on the lack of performance or game results / income.
So asking to reduce the F 22 to 6.3 can’t be justified just because the F 24 has an artificially reduced BR.
Besides that: There is zero need to drag British fighters (which saw no service / scored no kills in WW 2; just the F 21 saw combat) in the BR range of actual WW 2 fighters. The UK pilots are on average way superior than big 3 players - they need no “hand-holding” like US or USSR players - F4U-4B and Yak-3U are postwar hardware.
It’s always compression, even the rare occasions where things are at the “wrong” BR it’s usually because the compression means they cant go anywhere else (or it’s premium but that’s a different issue), and even then it’s only such a large issue due to the “power” for lack of a better word difference between the BRs that the compression causes.
Could easily be 6.0, just like the G56, J6k1 and Ki84-Hei.
But they are cursed by either legacy BR or simply turn well enough combined with great guns, which is more than enough to kill the average player that hardly bothers learning their plane strengths nowadays.