Successor to Boron 2G/3G board options

We have bought a few prototype boards in the last few years in order to experiment
with several IOT applications in mind.
The Particle boards are truly excellent regarding their built in cloud connection
unlike Arduino alternatives. We tested in France and the UK.
But we are confused regarding the boards on offer.
Attached photo shows 2 Particle boards.

The Boron 2G/3G kit is now deprecated, all clear.

Hence we bought the M.2 SoM Evaluation Board as, we believe/understand , is the successor to the Boron 2G/3G kit.

The Boron 2G/3G size with headers is perfect for our application using terminal shields from Arduino.
The M.2 SoM is much bigger and does not have headers.

Is there another successor to the Boron 2G/3G or is the M.2 SoM board the best/latest alternative and continuous to operate for the foreseeable future taken the ‘imminent’ deprecation of 2G/3G services in some EU countries?

We need the boards to gather simple measurements and control a few relays.
Don't want to install boards which will be obsolete in just a few years.

The M.2 SoM (M524 or B524) is the recommended SKU for Europe at this time.

It is possible that there could be a Boron form-factor LTE Cat 1 device in the future, however the problem is that the EG91-E cellular modem on the M524 and B524 SoM is too wide to fit in the Boron/Adafruit Feather form-factor.