There are other online platforms starting up and they are usually based around an alternative marketing strategy, and usually - but not always due to political positions. They are perfectly legitimate opportunities, but most are still small - but they are growing. Examples would be PublicSquare, Rumble, and many others.
There are also options that do something called "native advertising" - which means the ads have the appearance of content on the website - like you might see on FoxNews, or CNN. These are generally referred to as Ad Networks, and it isn't just news websites you find them on. You also have the opportunity to geofence these ads - which means you can target a single building, event, or area of a city. A few of these opportunities are with companies like: PropellentMedia, MediaVision2020, AdCritter, and more.
Although we haven't worked with any of these yet, our experience in working with most platforms over the last 25+ years would increase your chances of success on these. Let us know if you want to give any of them a try.