Overcoming a limit of number of devices tethering

Hi,

Apologies in advaance for asking what may be a very simple question but I am really not very clued up about these things.

I am using a 4g mobile sim card in a router that I have purchased as my fixed line broadband speeds are awful where we live, the issue has always been the limited downloads.  My provider have just launched a deal with unlimited download but one of the fair usaeg policies is that you can only tether to a maximum of 11 devices which we have more of in the home and don't want to be cut off.  The sim is meant to be used in a phone but I know it works in the router.

My question is if I use something like an Access point or a plug in wifi extender will that just count as one device connecting back to the main router no matter how many devices are then connected through the access point/extender.  It was a thught I had to try and get around the limited device connections and wanted some guidance if at all possible.

Many thanks in advance.