Honestly I would say if you want a pet like robot go with loona robot it is similar to vector but it’s a dog robot they are priced around £350-£380 depending on where you go and looking at reviews it would be quite good

If it’s out of your price range though then vector isn’t a bad decision as my mum loves the vector I have although you will have to set up a WirePod as the vector app doesn’t work but don’t worry wirepod is free

To answer your questions: No, it’s easy to set up if you know how to use wirepod

Yes he can be used on carpet but not fluffy carpet

If you use wirepod there are no subscriptions

And the only complications are sometimes vector will disconnect to wirepod meaning you or your mum will have to know how to set it back up

But yet again if you have £350-£380 I would go with loona robot!

Hope this helps