Looking for whatever with low power consumption.
Found modules on mediatek, download documentation for SoM (System on Module).
You scroll through in search of how much the chip consumes.

Required packages apt install fontforge и pip install fonttools.

Let’s decide on the necessary glyphs: we need Latin, Cyrillic, special characters, including some Greek symbols (ΣΩαβγμ), Greek analogues that are similar in style but have different codes (∆∑µ), and a few more that can be used somewhere in the text or as elements to replace graphics (♪♫♬).

Why are there multiple variants of similar glyphs with different codes?

Because the µ (mu U+00b5) symbol and the Greek letter μ (mu U+03bc) in extended fonts can have their own glyph with different shapes, or, conversely, a common glyph, where similar characters in shape refer to the same glyph. Or, for example, the Greek Σ (Sigma U+03a3) is not the same as the symbol ∑ (summation U+2211).
But perhaps these symbols look the same on your screen.