If you don't trust the development process then your only options are to run old software or manually audit the codebase. I don't think running old software will protect you from malicious code injection. This attack vector doesn't work by stealing your coins directly, instead it weakens trust in the whole bitcoin ecosystem and crashing the price. It doesn't matter what node software you run when your bitcoin buys you less goods and services than it used to.

As for actual long-term fixes to this problem you should look into libbitcoinkernel, it will enable a plurality of consensus compatible bitcoin node implementations.