4g router with LibreCMC?

I had not noticed before that this router was supported by libreCMC. Perhaps you could ask if it would be possible to have it also in the latest version.

I suspect it is because the update has removed support for a lot of hardware, as indicated in New Requirements [1]. They have removed support for hardware that "has less than 16M of flash and 64M of RAM."

However, the removal of support for the GL.iNet GL-X750 must be an error, as it has 16 MB of flash and 128 MB of RAM, as can be verified in its technical specifications [2]. So I would recommend that you contact the libreCMC team [3].

That said, I find it very surprising, in the first place, that there is 100% free hardware that supports the 4G mobile network, all cellular modem requires blobs [4]. It is most likely that the 4G modem has updatable proprietary firmware and that libreCMC simply doesn’t update it and uses it as if it were hardware. Perhaps that could violate the GNU FSDG, but these are speculations, and I would like someone to clarify this point: if 3G/4G routers with libreCMC really work without updatable proprietary firmware inside their modems and with 100% free software as dictated by the GNU FSDG. Especially since, although the GL.iNet GL-X750 is no longer listed as compatible, there are currently other routers like the GL.iNet GL-x300B, which remains on the compatible list and has 4G.

[1] https://gogs.librecmc.org/libreCMC/libreCMC/wiki/v6_1#new-requirements
[2] https://openwrt.org/toh/hwdata/gl.inet/gl.inet_gl-x750
[3] https://librecmc.org/contact.html
[4] https://forums.puri.sm/t/is-thales-5g-card-free-proprietary-blobs/16007/2