Can I add a 4G/5G modem to this? If so, that would be perfect!

I recently came across a WIP full-fledged smartphone based on the CM5, called SPIRIT <https://github.com/V3lectronics/SPIRIT>

They use the EG25 cellular modem <https://www.digikey.pl/en/products/detail/quectel/EG25GGB-25...>, the same one that is used in PinePhone devices