Public Shaming

I work for a small firm, there’s only 15 employees and I report directly to the owner of the company. My boss (the owner) and I have never had a one on one meeting despite me trying to set meetings in the beginning (I eventually gave up). Instead, he runs all communication through public slack channels with all 15 people in our company reading everything. for whatever reason, he will never respond to one on one private DMs and chooses to only communicate publicly. On a daily basis he will shame members of our team for mistakes and and interrogate them. He will call people out by name and say they are poor managers, and such. For example, this weekend I took PTO Friday to Monday and returned today (Tuesday). Before I left I added all projects to our system and wrote up a doc for our project managers to follow. Yesterday, while I was on PTO, a deadline was missed and I didn’t know it had been missed until today. My boss started off the morning shaming me in a public channel asking me why the deadline was missed of which I did not know because I had set everything up for my team to handle it while I was away and explained that. He then proceeded to tell our whole company how unhappy he was with me and how I can’t get simple tasks done and that he didn’t care if I was PTO, PTO was not an excuse and even while on PTO, I should be checking in and am responsible for deadlines. Mind you, this was a super small almost insignificant item. Multiple people on my team privately messaged me afterwards apologizing and saying it was their fault and I had made the direction & timing clear to them & they had dropped the ball. At this point I’m not sure how to handle communication between us. To make matters worse, I am pregnant and feel as though I have been the target of his public shaming more and more since I told him about the pregnancy. Yet, I haven’t missed a day of work since my wedding 8 months ago, & my pregnancy is not interfering with my job. I feel as though not only is the constant shaming an issue, but at this point I think my boss is trying to make a case against me to fire me/avoid having to pay my maternity leave as the last couple women who left on maternity leave never came back and he was very upset. So I have three questions here- 1. how would you handle communication with a boss like this? 2. How would you respond to the public shaming? 3. How should I go about navigating the rest of my time here while pregnant? I have 5 more months left before I’m due and originally planned to return after maternity leave but am now on the fence.