I thought you don't need to use router since TP link deco is already a router itself, no?

I need to recalculate the savings of buying pack of 3 instead of 2+1. If not much difference than I might go for 2+1. Otherwise it wouldn't hurt having more than less.

Thanks for sharing.

I did not. However you could buy the 2 in a pack and then buy 1 standalone later if it doesn't suit your expectation.
No I'm using the default unifi router.

Go to lazada or shopee and type tp link deco m5. I bought the 3 in 1 pack

It's connected to the router via cable. I didnt consider disconnecting it before.