Unfortunately it’s down to the app developer to update the app to keep it compatible with future software revisions so you’d probably be best to reach out to the developers involved.
Yeah, I know this, and have already reached out to a few of the developers. None have responded yet. This isn't surprising, as a lot of apps I use are made from some independent developer, basically just some guy doing apps on the side.
Many other big developers just stopped developing for tvOS. Some pulled their apps from the tvOS store, but many just abandoned their tvOS version of apps and still update the iOS counterparts.
A few, like the Ducktales Remastered app, are no longer available to purchase on any of the app stores, but are available to download if you already purchased.
But, it isn't all on the developers, imo. If Apple's new OS versions break apps, the user should be able to go back to a version that works.
Not having the ability to go back to old OS versions on tvOS and iOS has really screwed me when it comes to app support. Also, not being able to back up an ATV has also screwed me a few times.
I have been slowly distancing myself from purchased digital media, and going back to physical media when I am able to, but the latest incident with tvOS 14.6 has pushed me over the edge. I decided that I am just not purchasing anymore digital games.
I will play them if they are apart of Apple Arcade, but not spending any more of my money on games that could be abandon at any moment.
Three decades ago, I purchased Ducktales for the NES, and I still have it today. I can play it anytime I want and don't have to worry that an update might break things. Digital media has basically destroyed that.
