I think you have to create new account anyway. At least that’s what I did for YouTube Music. Because I don’t want to change home country of my main account and I even think you can only change country once a year or something, so I created new one, using VPN set to Turkey, and now I have family pack for around 1.20€ - 1.80€ (this month it was 1.20€), up to 6 users. But this is only YouTube Music Premium, without YouTube Premium.
Thanks god I have unlimited 150/50 4g internet at home for around 42€ per month. This month we downloaded around 5.5 TB of data. Also small town, countryside, no stop lights, no businesses other than bars and shops. There is only one stop light in whole region. And whole region is getting fiber optic. We had DSL, but speeds were terrible.