You should create a Deco router, to be sold individually that included a 3G/4G/5G backup.

Something like M9++, P9+, M4+

But only one per type. e.g. M9+ has zigbee, P9 has powerline, M4/E4 are just normal. Something that can cover all backhaul options, but the smaller amount of products, so support can be concentrated.