So - I wouldn't say that we're yet at the level of SimpleX - it's been in the works for much longer and you're right, they go to very extensive lengths to hide metadata.
The goal for nostr:nprofile1qy88wumn8ghj7mn0wvhxcmmv9uq3wamnwvaz7tmjv4kxz7fwwpexjmtpdshxuet59uqzqawhxlp5wfr3q2wyfpmtxvxj9ppg3fp80x6erghdfk4pcmq8a7hhwp9puf is to get that far for sure though. Like nostr:nprofile1qythwumn8ghj7enfd36x2u3wdehhxarj9emkjmn9qyg8wumn8ghj7mn0wd68ytnvv9hxgqpqlxzaxzge0jq9u9cecucctdt5lslwgp7hcxmp2l0wn8r2ecjenwasfxlphq said, you can already create as many accounts on White Noise that you want - using throwaway keys/identities if you'd like.
We'll definitely be adding tor (and maybe i2p or ohttp) support next year too.
What relays can see at the moment is limited to:
1. A group with a given group_id value exists. (relay doesn't know how many people are in the group or who the people are - relay can see a relative amount of activity is all, e.g. are there lots of messages or few). These group_ids can rotate for each group AND groups can run multiple group_ids simultaneously to obfuscate that relative amount of activity too.
2. A given pubkey is enable to chat using the Marmot protocol (which is our protocol that underlies White Noise but can be used by any Nostr client). e.g. that a given user has a key package published.
That's all.