Just to note, the NB FuelCell SuperComp Pacer is not classified by World Athletics (WA) as having a stack height of 25mm or less. So not approved by WA for track races. OK by WA for Road and Cross-Country events.
There are reports out there that the stack height of the SuperComp Pacer is 25mm at the heel. That is not particularly relevant since:
(a) WA have classified the shoe based on the assessed stack height at the specified distance from the rear of the shoe; and
(b) from 1 Nov 2024 the relevant WA stack height requirement will drop to 20mm.
The WA Approved Shoe List (as at 28 March 2024) is here:
https://worldathletics.org/download/download?filename=82f04a0a-73a7-45f8-a3da-c41ab38964eb.pdf&urlslug=World%20Athletics%20Approved%20Shoe%20List%20(as%20at%2028%20March%202024)
While the OP is looking for a non-spike shoe, the adidas Adizero Avanti TYO spike shoe is essentially a racing flat that can be used with super-short spikes or without spikes and is approved by WA for all distances on the track.
Hope this helps.