I'm pretty pessimistic about decentralized (blockchain-based) apps as well, almost all projects have been overtaken by speculators and fraud seems to be rampant

I'm pretty pessimistic about decentralized (blockchain-based) apps as well, almost all projects have been overtaken by speculators and fraud seems to be rampant, so I would not go near any of those. There really is no need to use blockchain technology to build decentralized infrastructure, most Internet 1.0 protocols are decentralized & federated and none of them relies on cryptocurrencies or a blockchain to function. So, sorry, but for me this whole movement is BS and seems more like a pyramid scheme than a real effort to build something useful.