Yes, Trump conducts federal business on his private property, or so they say. The emoluments clause and his likely violations long since ceased to grab readers and fell off the headlines.
I work in an average Washington, DC office building. In other words, the offices listing their addresses here rarely open. Some appear to be PBMs or somehow in the health insurance industry, others auxiliary offices of foreign companies.
Sometime ago, having found a law firm with both DC and Phoenix AZ offices, I called the Washington, DC office. The phone message rolled over without an option for leaving a message. The recording lacked a menu of extensions for reaching attorneys or paralegals. I waited the three hours for the Phoenix office to open and finally got a human voice.
I inquired about the Washington, DC office. The administrative assistant laughed lightly, saying she was not surprised. In other words, the office largely is empty. Somewhere in Phoenix an attorney or two display framed DC Bar certificates. I suspect somewhere in their advertising they claim to lobby or litigate here. I begin to wonder whether the phone in fact has no physical reality, if it is just a line with a recording, hidden somewhere in the depths of a server farm. I shrug my shoulders. What would you expect.
My own contract manager has its primary office in Chicago. While it leases 1.5 floors, currently only I, two other attorneys, and a part-time receptionist ever show. Just another DC office.