I would say, text requires more effort (at a minimum, typing is slower than speaking); but it pushes you to do things that you should do in speech but rarely would do spontaneously.

Most Japanese people are sooo slow in speeches in English that there will be too much of those you-shoulds to the point that just typing would be easier.

It also allows the other person to take their time to understand and reply. They can use online translation tools etc.

(Edit: Now that I read this: I should try writing e.g. Chinese using these tools, next time, instead of defaulting to English. My mother language isn't English, but it's pretty close, comparatively speaking.)

A pattern I often end up with when there is a large language barrier: begin with long async messages that take a minute or two to write. End up with brief sync-ish messages as things get more detailed and we share more context.

Yes, that makes sense. One of the things that has made Discord, Slack etc. so important (and could have done the same for IRC if people weren't so intimidated by it) is that users feel free to switch between sync and async modes as appropriate.