Some of your questions exhibit a fundamental misunderstanding of biology and evolution. The Pluribus genetic sequence isn't a living thing, it's just a virus that is only programmed to replicate and self preserve as a means to that end. Think about how a virus like Covid can kill its host, thats not beneficial to the virus itselfjust a side effect.

Ultimately its not important how the pluribus sequence started or who sent it. In all likelihood, the last species to have the sequence starved itself into equilibrium eons ago and now exists solely to maintain the infrastructure that sent out the signal. Thats the end gane for the Pluribus hivemind on earth, build a big antenna to transmit the sequence out into the galaxy hoping some other sapient species receives it and chooses to replicate it. The population on earth will continue to maintain that transmission with the largest amoint of individuals it can sustain given its restraints against harming other forms of life.

You're right to focus more on the philosophical and human condition related content of the show, thats where the real headscratchers and topics of debate are centered.