In this post I'm going to recommend Slack, although I'm conflicted about recommending it. It is a communications platform, and a very good one. As such, it would allow the manager to ping me (or anyone) more often and more consistently. This would result in me having less available time, because I will increase my availability to the manager. With that said, I am an expert and a professional, so in the spirit of Correctness and Doing a Good Job (TM) I am inclined to provide this recommendation.
Slack is one of the best communication platforms out there. Now it's owned by Microsoft. It is free but not open. In the silicon valley it was our primary means of team communication: better than sms (android notifications are the same, and copy-pasting works much better in Slack). More immediate than email. Allows video calling. Keeps extensive audit history, and is cross-platform and multi-device unlike SMS.
A disadvantage is that if you haven't used slack, it is another comms platform, and as such it distracts from other comms channels that you might be familiar with. Still, every full-time distributed team that I've worked in full-time, used slack.
Similar tools are: discourse, whatsapp, telegram. To give you an illustration of how powerful these are, both biggest AI tools (chatgpt and midjourney) use discourse as their primary/only interface.