MacBook Pro running Sequoia 15.5. File sharing and media sharing are on. Apple TV and Mac are on the same wifi network and use the same Apple account. It worked great for years, then stopped working.
File Sharing is for computer-to-computer sharing through Finder network disks. It doesn’t need to be on for Home Sharing of media files. It is fine to leave it on, though, if you want. They’re independent.
Home Sharing settings may be delicate, in that they have been lost or broken somehow, in part or in whole, in your configuration, despite how the settings look at first sight. Try turning the settings off, then on again.
Photo sharing through Home Sharing has its own sub-settings in the Home Sharing settings. It can point to either the Photos library or a photos folder. Please set those settings again all over as well.
For testing the network connection, try if you can AirPlay or Mirror anything from the Mac to the Apple TV. That would use the same network compatibility as Home Sharing. If one works, then the other can too. If AirPlay doesn’t work, then you may need to re-examine the details for your home network.