Well, at this job. At my previous job, which involved making software for and supporting a call center (on behalf of health insurance companies), I would get texts sometimes as late as 10pm saying that something had gone down and they needed me to get on a call and tell the server teams what we needed to be back up. The department was a skeleton crew the last couple of years I was there and I was the only guy that knew everything about our phone systems so they were pretty reliant on me or else 90+ agents would be twiddling their thumbs.
I was on Teams calls for up to 16 hours sometimes (through the night and into my normal shift the next day) trying to get things resolved (and the people I was on a call with would tell me "I'm going home for the night. You'll now be talking with Y" So they didn't have the same skeleton crew they forced our department to have.
It was bad. They had all sorts of problems at the data center too, and/or made breaking changes without letting anyone know. It got a bit more stable near the end, but man it was horrible for at least a year and a half straight. This was a major corporation also.
I decided that would be the last job in phone systems I would have, and I'd never let myself get into that bad of a situation again.
Discord would probably be better since Slack’s pricing favors business use. We lose our old messages on the free version of Slack, but the all-or-nothing per-user monthly cost of a paid version prohibits our group from upgrading. You either upgrade everyone in the group or upgrade nobody.
The way that Discord’s premium features are based on an individual person’s willingness to pay rather than the entire organization is definitely a better model for personal use.
I also don't have Slack installed on any personal devices. If I "have" to send something I'll install Slack and then delete it right after.
More often though I'll just email my work address with the message I want to send and then take care of it the next day.