Sonim makes ruggedized equipment (XP8 is IP68/69 rated)
I feel this market may be somewhat easier to penetrate. In my experience the civilian segment of the user base tends to be amenable to alternative systems and looks to reliable core functionality more than the latest “infotainment appliance” features.
[Personal note : I am a user, my technical knowledge is limited and haven’t worked in SQA for about 20 years now – but I am open to testing. or other assistance within my skillset]