Connected Devices

Hi guys,
Sorry for this question that is probably a silly one.
I’m not technical at all so please go easy on me.

I’m looking for a mesh solution for my home.
Looking at the product description some top routers state “for up to 25 connected devices”
What is classed as a ‘device’?

I have well over 100 internet connected devices such as hue bulbs, smart plugs, cctv cameras and all the usual pc’s, tv’s and tablets etc.
Surely these top routers can cope with a modern home with all these devices?

Does “connected devices” mean tablets etc or does it actually mean everything such as bulbs etc.

Sorry if this is obvious but to me it isn’t.
Appreciate any help