As of the conditions in most countries right now, I would say yes, technically. I think trying to establish some kind of gatekeeping community purity test is an excercise in futility, many of us have to live within capitalist systems. I myself work in upper management (which is probably not common for many communists) and also sell my own labor for less than it is probably worse to a faceless corporation. Now, that doesn’t mean you should go on to found a company exploting people’s labour and go “It’s okay, I am really a communist guys!”.

In much the same way that a country goes through a transitory process to become a communist nation and does not simply remove all capitalism overnight, neither does an individual. Several prominent communist leaders came from wealthy backgrounds themselves.

Now that said, while not impossible I think very few landlords would be advocates of socialism, as that is a self-defeating proposition. People tend to do what is in their own class interests most of the time, and that is unlikely to be socialism for a landlord. It’s absolutely possible to advocate for positions outside your class, we just don’t see it as often.