I had both I switched from Marriott to Hilton. First for my destinations on business travel I generally had better Hilton hotels (nicer, cleaner, more modern, more options like restaurants, bars, gyms etc.). Second for the rewards, I found Hilton better overall for a variet of reasons. Last thing - you may want to consider something like the page below. They map out the chains across the US and also factor in the percentage of their chains. Companies like IHG have more but they are dominated by Holiday Inns. Marriott it's Fairfield and Courtyard (some can be nice) and Hilton it's Hampton so you may want to consider this as well depending on our needs of a hotel and their geographical locations.
https://www.scrapehero.com/largest-hotel-chains-in-the-us-location-analysis/
Important thing to clarify, did you acknowledge the knock? If you didn't and the computer said that the stay had ended it was possible they thought the room was empty. Hotels.com is not the source of truth for your booking, Hilton's computer system is, and I have heard of many times where a 3rd party booking site will not correctly update the reservation (which is entirely on the 3rd party booking site, not Hilton).