Well, on iOS to have an app-like experience you either connect to your PC every week to re-sign the app, pay ~$15/yr to sideload without a PC or pay $6/yr to get Turkish YouTube Premium, which also gives you YouTube Music Premium and you can use on all platform. Sounds clearly like an exploit to me.
Scan the card’s QR code in the FUPS app. You now can use the card to spend money from your FUPS account
Use Revolut to convert money to Turkish liras, and use the „Card recipient” transfer option to add money to that account with basically 0 fees.
Now to buy a family subscription, I personally used an android virtual machine, on which, while connected to a Turkish VPN, I made a new account on a random Turkish address. Then just bought the sub in the YouTube app.
Afterwards, you can invite others to your family.
But, they won’t be able to just join, they need to go to pay.google.com -> Settings -> Close payments profile
Then they need to add a CC to their account (doesn’t have to be Turkish), but make sure that they put a random Turkish billing address to that card. Wait ~10 minutes, and they can join the family, and after they’re in, they can re-do the google pay stuff to get it back to normal. Won’t kick them out.
Sometimes one might have issues with delayed opening of GTK apps, but I’m pretty sure there can be multiple causes. All misconfiguration, so it would be weird since you’re on Kubuntu.
Anyrun is pretty good, I agree.