I have a Samsung A56 and tethering doesn't work. The pop menu that normally opens up on USB connection doesn't show up at all.
I tried the cable that came with the device + another one to no avail. With each cable I can easily tether to my laptop and internet/data transfer work fine. Tried the USB connection default at developer options but that didn't help either. Seems the router/phone combo is buggy. Any suggestions?
Works for me with a Pixel 8a running Graphene OS.
Check your power supply and try to restart your phone.
Applied all system updates?
Look for dirt in your usb connector.
Tethering and power supply is done through separate USB ports. USB-A connects to your modem and USB-C for power. It's a bit of cable spaghetti when you do all that.
Just tested cable tethering with an old 20k mAh external Anker battery. It works fine, but only through one of the battery ports.
If the Slate7 needs 9/12V as mentioned above, any battery that supports PD 2.0 (or greater) w/ 30W of power should work fine.