They will expect something is/was wrong. Simply because people organically don't communicate like that. There is no N minutes pause between prompt and the message. Having separate communication prompt is signaling for bracing or softening, i.e. delivery of bad news.
Sure, a lot of people learned to cope with this, but that's definitely not normal communication. It's also wasting other people's time and showing lack of respect. Having someone wait on hook for 2 minutes while thoughts are being typed out is exact same type of power move as "yeah, I called you, but wait a sec till I finish my crossword". Is the other person online presence really indispensable to a degree that the thoughts cannot by typed out without it? As a counter move (if someone wants to be mean) you can respond "Hey, I'm here, but I'm starting my focus session right now, so I'll check my Slack/E-mail/IRC/Teams in 45 minutes, what's up?"
So yeah.. don't do this in professional communication.