Pretty sure people have done the maths and to approach the levels of efficiency that say meat has you'd be consuming a lot more calories.

What does meat's "efficiency" have to do with anything related to caloric intake? If I consume 1000 calories of meat or 1000 calories of vegetables, I've still consumed 1000 calories. I can only assume you mean I would have to eat a larger quantity of vegetables get the same amount of calories, and that's not the argument you think it is when people by and large consume too many calories and don't get enough micronutrients as it is.

but your quality of life will be worse, so yes I count that as those meat products being necessary, in spite of the environmental damage

I'm not even a full vegetarian, but even I know this is just self justification for what you want to do. One of my partners is a vegetarian, and I cut back on like 80-90% of my meat intake and my quality of life (like energy and general physical/mental wellbeing) is the same or better than it was a few years ago.

The only good points you made was about food waste and lab meat, the rest is just cope.