Per this Reddit thread, indexing services like Torrentio cost money to run and will stop functioning if their servers go down. Thankfully there are alternatives to Torrentio—such as the free Jackettio plugin and the paid Debridio plugin—to ensure continued functionality should anything happen to Torrentio.

Torrentio already becomes unstable under heavy load, so I would recommend using another service in conjunction with it as a backup.

You can selfhost some but mines are not for english content so can't recommand any

there's also bitmagnet, which is not a torrentio drop-in replacement, but it's a selfhostable public DHT scraper and indexer