What it seems you're struggling with here is a lack of clear definitions.
Yes, the unity of core cellular mechanisms implies an unbroken line of descent back to the origins of life. But that does not in any way mean the cells are actually the same. I think that you would find it instructive to learn about the puzzle of the Ship of Theseus, which is the ...
From experiments it seems you should better use dark mode if you want to prevent myopia:
Using optical coherence tomography (OCT) in young human subjects, we
found that the choroid, the heavily perfused layer behind the retina
in the eye, becomes about 16 µm thinner in only one hour when subjects
read black text on white background but about 10 µm thicker ...