Sybil attacks are not solved with the "Soul" bound reputation approach. This was mathematically proven some years ago by Harvard University phd student Sven[0]. See his impossibility results on "weakly beneficial Sybil attacks" and "single report responsiveness property". The blockchain crowd has not yet discovered this, fake identities are an unsolved problem.
Startups be aware. European Commission now has an official "26 000 000.00 EUR" "estimated value" open offer for SSI wallet solutions [1]. Prior for basic service called "EBSI" was 35 million, won by IBM Hyperledger. That now works, Dev API [2]. Upcoming Europe directive states that by 2024 all citizens can apply for a digital identity, if they want one.
(self-promotion..) State-of-the-art: Delft University trustless SSI solution with running code and field-tested zero-knowledge proofs. Scientific publication "A Truly Self-Sovereign Identity System", published at IEEE LCN conference[3]. Disclaimer: we got the government contract for doing privacy-first digital identity. We integrated our own Tor-fork based on UDP for solid privacy with verifiable credential stack, see Github deep link [4].
[0] https://dash.harvard.edu/bitstream/handle/1/4907301/Seuken_S... [1] https://ted.europa.eu/udl?uri=TED:NOTICE:309685-2022:TEXT:EN... [2] https://ec.europa.eu/digital-building-blocks/wikis/display/E... [3] https://arxiv.org/pdf/2007.00415.pdf [4] https://py-ipv8.readthedocs.io/en/latest/basics/identity_tut...