Before anything I want to say I have had bugs in some play throughs where even though I had no visible hotels I had one already due to me having one in that neighborhood previously and selling it to convert it into another racket or move it but game wouldn't let me since it's still registering old hotel.
Hopefully answering these questions will help you fix your issue.
Do you have a current synergy going in that neighborhood? example 3 of a kind is 3 of the same type of rackets, 3 casinos say. Straight is one of each, a casino, a speakeasy, a brothel and a brewery. Full house is 3 of one type 2 of another example 2 brothers and 3 speakeasy. NOTE! Rackets can only apply to one synergy. Can NOT have the same speakeasy apply in all 5 synergies ... hope that makes sense.
Upon having a synergy, after you take over a derelict building or buy a racket in an available building, what does it say when you hover over the grayed out hotel option ... if it's available now, then there fixed it, if not, what's it say? If it says there's one already there I'll cover that in next question, if it says your unable to due to having no synergy, wait a week to pass and recheck ... happens when you take over rackets but not so much when you buy them to register that quick ... not sure why but has happened a few time for me in the past so it must be a thing ... not too sure on that one. This next little part I am not trying to insult your intelligence but make sure you have enough funds/cash to set up hotel also ... DO NOT set up in a medium or large building, it does nothing more than waste that building, you get the very same in a small building and it's way cheaper.
When you are in the neighborhood overlay, the screen where it shows all the neighborhood information and where you can also see if you have synergies in that specific neighborhood. There are 2 places in that same screen where it would tell you if you already have a hotel in that neighborhood, one reads left to right and the other top to bottom and at the end of both it says hotel, if you have one it will be highlighted and a green check or X would be in the bubble, is this your case? If so, you have a ghost hotels somewhere in there and are good, it could be a bugged out one but it's there and you are benefiting from it and that is why you can's set up a hotel ... but it's there somehow. Now you may not have the same fortune in another neighborhood and will have to set one up. If this is the case just roll with it for the time being as I promise you there is no fix it to it right now. Either start from a save before that "issue" happened or start a new game is best you're going to get. If and when fix comes out in a patch it will fix itself when you go to upload your save and you may or may not get a notification but always check and see if it's still the case.
Now, when you do manage to set up your own hotel and see other hotels in the neighborhood from other factions don't freak out as that's normal and a thing they can do also. No, you can't take theirs and they can't take yours, hotels are off limits in this game. However they and you can lose that hotel if you lose all synergies in that neighborhood and you might find yourself back at square one with a ghost hotel later ... if it bugs out again. roll with the punches ... You may run into taking over factions empire that has hotels in shared neighborhoods and notice their hotel is t=still there and now you have 2-3 HOTELS!!! don't get too excited as it does nothing or multiply anything

I know ... you'll still only get the benefit from just one. I will try to find the game saves where I have this happening to show you.
Hopefully this works for you and you figure out how to set up your hotel. If you can let us know the results or if the issue persist let us see a snapshot of what's going on