Domestic US flights with expired passport

My passport will expire soon and to get a new one I must go back to my home country, which I plan to do in few months. I have a valid Visa until 2023. I would like to travel within the US before going back to my home country

Are you sure of this? Most countries issue passports to their citizens at consulates and embassies. (Of course, depending on the country and your place of residence, it may be more convenient to go abroad than to go to a consulate in the US.)

I have searched online and most results (including the official TSA website) say that it should not be a problem. Few say it may be a problem is the expired passport is my only ID. I cannot find a definite answer that does not say maybe / may / should.

I once traveled on a domestic flight with someone who had forgotten her foreign passport. She lived in the US but had no other form of ID on the official list. She did have a foreign driver's license, which they didn't look at at all, a photo ID from her employer, and a few credit cards and bank cards. They looked at these and asked a few questions -- the "personal questions" mentioned on the page, I assume -- which essentially consisted of verifying data from her credit report (former addresses, for example).

From this experience, I infer that you will probably be able to fly with your expired passport, but there may be a slightly higher risk (if still extremely small) of not clearing the security checkpoint. Clearing the checkpoint will certainly take somewhat longer, however, and will potentially be more stressful, especially if the agent or agents verifying your identity are unfamiliar with the procedure or are for some other reason inclined to be confrontational.

One option is that the emergency travel document that your country's consulate can issue you would probably suffice as ID for airport security checkpoints. However, the emergency travel document probably has short validity, and the consulate would probably not issue it unless you are traveling to your country very soon.