Just a little anecdote that’s relevant here. Around 10 years ago my girlfriend didn’t have wifi home yet (low tech family), so we spoke at night over landline, as those calls were free. And it definitely did feel like what some people here are saying: you could hear everything with no delay or cuts at all, the whole call just felt like she was there next to me.

They eventually setup wifi in their home, so we switched to VoIp calls, mainly so we wouldn’t block our families’ landlines for a couple hours every day. And the quality was so much worse...

The delay sometimes would be so bad that we had this technique where one would slowly count down from 3 and then say “Now”! Then when the other heard Now they’d say Now too, and the first person could essentially count the seconds. This way we could “slow down” our conversation to accomodate for the multi-second delay, which (thinking back) was like our own protocol for dealing with signal delay!