1NT is 15-17, denies a 5-card major, may have a 6-card minor, will only be 5422 if exactly 2=2=4=5 not strong enough to reverse. Nice 14 and 17 counts often upgraded, mouldly 18s very rarely downgraded.
(1) Diamonds
(2) Either the A or the K and at least 3-card support
(3) Natural FG. Either a slam try, or just looking for the best game. May not be that distributional if looking for a slam - 2452 is possible if it looks possible that we may want to play in diamonds but clearly many 2452s will just look for a 4-4 heart fit and bid 3NT without mentioning diamonds.
So, you have already shown the diamond fit. Do you bid 3NT, nominally to play, or do you bid 3S showing values in spades and doubt about strain? Or do you find something else to bid?

Help

1NT P 2NT(1) P
3♦(2) P 3♥(3) P
?