Pretty sure you can set up router to create wifi hotspot from ethernet.
https://www.howtogeek.com/213638/how...-your-devices/ This would be best way to go for permanent frequent use.
For occasional use you can create a wifi hotspot using a laptop or desktop. I have occasionally done this with linux where I had to go online with some wifi only gadget. Ubuntu has this ability built in, but there is a simple commandline app called CREATE_AP that does same on any linux. Think there are windows apps too. May or may not be free, dont know, never tried such in windows. Or you might manually do it, but app makes it lot easier to set up unless you are really knowledgeable with networking.
These apps can basically use whatever kind connection the computer is using for access, yea even dialup, and convert it to generate wifi hotspot to share the connection. Requires computer has a supported wifi adapter, either built in or usb or whatever. Some wifi adapters dont support this.
As using an usb ethernet dongle on a tablet, no idea, depend if the tablets operating system supports it. Though if you search long enough probably find instructions somewhere. Since tablets designed to be ultra portable, guessing not lot demand to used wired connection for internet access.