@praveen Why would you want to?
You use and potentially fork Firefox because it's currently the only non-Chrome option in its domain, and because it's going to take very large amounts of time, money, and effort to build a complete replacement.
None of this applies to SimpleX. There's no big asset there. It was not some astronomical effort to build. You don't need it for interoperability with the existing web. It's an over-hyped piece of garbage designed to make money and influence for nazis who built it. It does not solve any problem anyone has.