How to build psychological safety on a distributed engineering team

I've been on remote teams for over a decade now, including a good chunk of that as a lead.

Argue against yourself during discussions, especially workshops. Other than coming to better solutions together, you communicate that it's ok to disagree.
If there is a conflict of interests or misunderstanding, whiteboard it out with a tool like Miro or Mural. Get everyone looking at all data points, so you can 'see' each others' perspectives.
Use one-on-one meetings to get to know each other better. Play games or even explore hobbies. One of my team member has a hobby of winning games of online chess against me.
Explore if each person knows what is expected of them. The less they will be surprised by a changing expectations, the safer they will feel.
You need to be ok for people to make mistakes or fail. As long as they take responsibility and don't turn it into a pattern, consider it an investment in their internal motivation on the job.