Wait for benchmarks. It may well be a "cheaper ssd" but time and performance moves on. It will still likely be > 1GB/sec and that is (especially for an MBA) "plenty fast enough". As in you will not notice the difference.
Also... apple don't change price mid-model generally, and since the last MBA was released SSD/flash prices have crashed. Like... $100 australian for 500 GB - RETAIL now.
I have both SATA and m.2 NVME SSDs in my desktop in my sig and you honestly can't tell the difference speed wise, although in theory the m.2 is at least 3 times faster.