It seems there a bunch of contracts that are "broken". They hang for a huge amount of time before returning data or running out of gas. This is making the Substreams hang forever.
A possible solution is to set a low amount of gas of eth_calls that you know are cheap and should return quickly. This way, you would simply get a timeout and you can handle this timeout in your code.
See: https://discord.com/channels/666749063386890256/982135810742697984/1272200000633569280