wow - it took over 15 minutes to believe my eyes

thanks for coming back and sharing, OWD.
So "sentience" might often be used as a "class distinction"... and as such I would regard it erroneous. Mostly to the fact that humans tend to look at other organisms from outside, caught up in their own conceptions and delusions.
This "mind" most of us are using for determination can actually pose a greater hurdle than it comes as a blessing - depending on its usage.

I'm not certain you are there, but I follow on that slope of "capacity". In "perception", "processing" and "expression" (of sentience) - this said we're still to understand exactly how much plants (and animals) do communicate with each other (on which topics) and to exactly read their way of expression. One might be surprised
what is in the craw of a crow. Maybe a tree neither feels the necessity to mourn nor to suffer, or simply does it in a way we can't understand it due to our limitations.
From the first part of your response I take one thing:
Is "sentience" applicable for the
human level alone? Or are we trying to compare a... MIG23 with a... mountain bike? Both specifically designed for their environment and (better) not to be exchanged for one another...
From the second part of your post I take:
Though it could take less animal products to feed a human being sufficiently than it takes plant products (the current dietary habits of many carnivores set aside), not ethical - just maths.
A cow for example feeds on a variety of plant life, but grazing itself mostly involves "grass". Itself a rather simple and perennial plant life form. Can be mowed, grows back...

But before now embarking on a rather lengthy journey, it's helpful to cut it down: (disclaimer: I personally oppose the current industrial farming of livestock - no question that it's inhumane and perverted; poses the source of unnecessary suffering on a large scale; spoils the environment to an intolerable degree. Which is why I do subscribe to "the numbers game" myself.)
Have you ever considered that this "suffering" referred to, might be a mere human conception?
When looking at nature, it is apparent that (physical) life and death are two inevitable components. Pain as such is also... inevitable.
Is "suffering" a human invention? A mere concept?
Don't get me wrong: empathy, true empathy is a gift. Projection on the other hand is a curse.