How can I get IP connectivity on my non calling tablet without using WiFi?
If your device supports USB OTG, then you should look into a wired Ethernet adapter.  Depending on the specifics of your tablet, if it works, this is the best solution.  Android SE, example how-to, XDA, example cable to let you charge and Ethernet (eBay).

If you're not rooted, or don't have USB OTG, the next best option is to buy another WAP of the fastest type of WiFi that your table support and put it near the tablet.  If you normally use 2.4Ghz Wifi, then get one that's only 5Ghz, assuming your tablet supports 5Ghz.  A different band will reduce interference and let the tablet and WAP use their full speed.