The Hosted Service currently supports 32 networks. The Hosted Service is a free, centralised service run by Edge & Node, one of the core developer teams at The Graph.
The end of Q1 2023 reflects the sunsetting timeline only for The Graph Network-supported chains. As non-mainnet chains become supported on The Graph Network, their hosted service equivalents will sunset gradually to ensure developers have time to migrate subgraphs to the decentralized network. https://thegraph.com/blog/sunsetting-hosted-service