Connecting All Devices In My Apartment To Router & Then To A HOTSPOT

Ok so basically I live near an Optimum hotspot in Northern NJ. I have an Optimum account at my house (where the modem is), but my apartment is near an Optimum Hotspot which allows me to get internet using my Optimum Account from my apartment where there is no modem.

All my T.V.'s (TCL 65" & TCL 40") are smart and connect through WiFi through the hot spot with no issues.

Roomba, Kangaroo Doorbell (similar to Ring), the Roku remote from my iPhone, and an Amazon Alexa (which I gave away) will not connect to this hotspot.

They are all "in range", and it is absolutely not a an issue of not getting a "good" connection.

ROUTER ISSUE
I bought a TP-Link (TL-WR940N) Router thinking I could simply use the router as a "repeater" and connect everything through there since the issue seems to be that the devices can't be found on the public network.

What/How can I connect everything together without actually buying another plan?

I appreciate anyone's advice in advance.