The problem of insects and rain clogging the suction holes was solved by applying sinterization, creating a metallic ‘aerosponge’ which also had the net result of vastly increasing tensile strength. You would learn this if you read Renato Vesco’s book.
As far as LENR theory, there are dozens of theories just like there are dozens of theories of gravity. But gravity is very well described mathematically, we just don’t know why. There is also no widely accepted theory for high temperature superconductors.
What LENR needs is not just a theory or a host of competing theories, but a single, generally accepted theory to guide research and investment by offering benchmarks and goals. Otherwise, the time and investment cash pub into the field is all too likely to be a loss.
High temperature superconductors at least have proven experimental results and a handful of commercial products. LENR is not even at that stage yet. That can change quickly, with modern physics having the great virtue of honoring experimental proof as validating theory.