Need data on for voicemail notifications?

[neonpink]

I recently purchased an iphone 12 mini. This is my first iphone. I am able to receive voicemails but I don't get notifications unless my data is on. Is this true for every iphone? I don't want to leave my data on 24/7 but I'd also like to be notified about voicemails. Any insight would be appreciated, thank you!

 

[now i see it]

Data requirement is because of visual voicemail. It uses a miniscule amount of data.