It won’t be a NE.
NE was the internal Mazda reference to the Abarth 124 Spyder. NF was the internal reference for the Fiat 124 Spyder. The acronyms refer to a platform family, not necessarily sequential development.
For instance, the platform with a D prefix refers to the sub compact FWD, which started with the 1986 Mazda 121. Currently, the DJ, DK, DL, DM and DR are in use. There has never been a DN, DO, DP or DQ platform.
The next all new MX5 will be the NG. NE won’t be reused as it refers to a former model.
Mazda has filed between 2019-2021 various patents on mild hybrids, many of which feature a MX5-like vehicle (though maybe don’t read too much into the actual drawings). eg
I hypothesized a while ago that the basic ND platform will be life extended by use of a mild hybrid. A mild hybrid is the only way a petrol MX5 can remain on the European markets, including the UK, beyond 2030. There will be two versions offered; a conventional petrol car, with a small capacity turbo motor, and a hybrid. The hybrid will be auto only and a bit heavier with less storage space. From 2030, Europe will only get the hybrid, and hat might be enough for Mazda to keep a presence in the market. There is sufficient uncertainty in other markets as to when conventional ICE will be outlawed. ie. the US will likely still have conventional MX5s sold after 2030, albeit an increasingly aged platform, but likely with literally no competition.
Mazda will reserve development of a EV MX5 until technological progress in battery design can be sufficiently progressed to meet weight goals. That development won’t be driven by the MX5; it doesn’t sell enough. But they will be looking at Toyota etc. An EV only MX5 will actually make a RWD MX5 a lot easier than now, in terms of platforms, as EV architecture is a lot more flexible than ICE. You can place the motor, the mass, whereaver you like. ie. MG, like others, has incorporated the battery into the Cyberster chassis, so while the car is quite heavy, the COG is very low, and likely, like the MG4, they have achieved 50-50 weight distribution. By that time, around 2032-33, Mazda will have redefined what the MX5 is all about (ie. getting away from the gearbox experience, unless they implement Toyota’s fake gear change).