I got a kobo arc 7 stock on wifi also (without keyboard!)... but I was able to SOLVE the issus with windows 10 PC.
Here is what I have done:
1. Download the GOOD tls-update-ota303.zip file on archive.org (
https://web.archive.org/web/20210220...ate-ota303.zip) Don't go on the KOBO site, the file is corrupt...
2. Plug your KOBO with USB (with battery chaged or wait a night).
3. Looking for ARC 7 in "This PC", then copy the file "tls-update-ota303.zip" to ARC 7, not in a folder, but in the root.
4. Rename "tls-update-ota303.zip" to "update.zip".
5. Unplug and restart your tablet. update firmware start.
6. For me, I was able to go online after and I got another update for the device. Everything works fine now.
Regards! Have fun.
Patrick