The protein argument is probably one of the worst of the food uneducated. I could flip your argument and ask about actual nutrition. What vitamins, minerals, amino acids, etc does meat provide? Very few.
Protein? Peas, quinoa, beans, nuts, tempeh, leafy greens, seeds, and the list goes on. The difference is something like quinoa is that, compared to any meat, it is calorie for calorie more nutritionally complete.
Finally why are you focused on protein to begin with? And how much protein is required for you daily? Overconsumption of has shown negative effects:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4045293/
