When I turn on WLAN hotspot I can connect from my Linux laptops
However I have no internet access
I can work around the issue by running
ssh phone -D 1080 & chromium --proxy-server=“socks5://localhost:1080”
This works for web browsing, but not for anything else
Has anyone else seen this issue?
One theory (hypothesis):
So you’re using your wireless data to provide internet to your laptop, right? Maybe your carrier, like mine, doesn’t want you doing that and is intentionally blocking you. Mine does. SSH-ing thru would encrypt the traffic and prevent them from recognizing what you’re doing. In my case, using a VPN also accomplishes the same thing.
Wow quick response 
Are you using the VPN on your Sailfish device?
Sometimes I do, particularly when roaming on my data plan. When the kids were doing remote school, they could work on their iPads in the car if necessary (very handy if they’re doing that because we’re racing to get a Covid-19 test!). Configuring an OVPN VPN on SFOS is very quick and user-friendly. (Haven’t tried other VPN types.)
Your Provider will not see this in your LAN. Maybe it is forbidden to use such SIM in a router an so its blocked, or your telephone is unable to use tethering (of broken provider software).
I would think there is some trouble of firewalling and/or routing.
Maybe an “iptables -L -n” on both devices shows more? Or “ip r” on the laptop?
It was described a long while ago that it may have to do with protocol. On your mobile data settings, do you have IPv6 or Dual set? Might try just IP and see if that solves the issue.