So you believe bitcoin is not secure, but it IS.
IMO, Bitcoin (POW) "IS" secure because government hasn't really try to take down the network yet. Any hardware related consensus mechanism will be overtaken by government in the future, just because they have the most resources.
I definitely think that proof-of-work is going to be phased out soon, though proof-of-stake isn't much better, they all require specialist hardware in order to run their networks, which is not something we should implement for later generation blockchains, a waste of energy can't be the best way to secure a blockchain. I notice that the major blockchains are starting to shift towards POS as it's definitely more environmentally friendly than POW, but it also increases centralization and the risk of a vector based attack so we should look for even better alternatives in future.
What about Proof of Transaction? I am in this
new project that created a new consensus mechanism, it seems to be an alternative from POW and POS. For anyone who is interested, there is a Proof-of-Transaction
debate bounty, debating to be the best consensus mechanism.