Forming good working relationships with employees?

I started a new job managing around 60 employees last month. I make their work schedule, help with anything they need, etc. The trick is, they’re all in a different state, and they work in teams on location. So they get to see each other face to face, while I’m a voice on the phone or email. (It doesn’t help that I sometimes struggle with understanding people over the phone)

I was a teacher, and I know how important positive relationships are when managing people. But when I call them, it’s usually during their workday so I don’t want to chat for long as each person is integral to the team running smoothly. Or they’re calling me to complain about something, which is also not a great time to chat about their weekend. I don’t struggle at all to form relationships with coworkers in person, but I’m finding it much harder with them being remote. I don’t want or need to be everyone’s best friend, but I think I need to be more intentional about building these working relationships. Any tips?