Hello ninoncsu23,
Thanks for reaching out to Apple Support Communities. We see you have some questions about songs not being available in your region, and we'd like to help. When you set up your phone, did you change your country/region settings for your Apple ID account? The article below can guide you on how to check on these settings, if needed. Just changing devices should not affect the country/region listed for your Apple ID account:
Change your Apple ID country or region - Apple Support
Use your iPhone, iPad, or iPod touch to change your region
1) Open the Settings app.
2) Tap your name, then tap Media & Purchases.
3) Tap View Account. You might be asked to sign in.
4) Tap Country/Region.
5) Tap Change Country or Region.
6) Tap your new country or region, then review the Terms & Conditions.
7) Tap Agree in the upper-right corner, then tap Agree again to confirm.
8) Select a payment method and enter your new payment information and billing address, then tap Next. You must enter a valid payment method for your new country or region.* Learn more about how to change or remove your payment information.
If everything is set correctly and has not been changed, delete one of the songs which will no longer play, and redownload again. Test to see if it can be played again.
If so, you'll need to repeat the process with the others.
Regards.