I discovered the best way to build pushup strength 

Do you want to be capable of doing this?
I can get you to this position in 6 months: If Youre Serious Comment below Pushups and Deep Knee Squats can be done anywhere Anytime.
This is a sampler of where you can get to in a much quicker time
Improve your health has to be the funniest thing when you focus on more than just strength. Be an athletic all rounder