>I don't have MDM on my phone (no alt-roots or anything). "Just" the 2FA, gmail and Slack. But I agree, I'm tempted to get the work stuff off and onto an old phone just to have the mental separation.

Gotcha. I encourage you to do so. I'd further encourage you (if this isn't the case already) to have your employer pay all costs associated with that other device. As it's their requirements that put you in this situation.