From Old English 'maest,' superlative of 'mara' (more) — unrelated to 'much' or 'many,' a striking case of suppletion.
Greatest in amount, extent, or degree; the majority of; used to form superlatives.
From Old English 'mǣst' (greatest, largest, most), superlative of 'māra' (greater, more), from Proto-Germanic *maistaz (most, greatest), superlative of *maizô (greater, more). The Proto-Germanic forms derive from PIE *meh₂- (great, large) with the superlative suffix *-is-to-. This PIE root is remarkably productive: Latin 'magis' (more) and 'maximus' (greatest) gave English 'major,' 'maximum,' and 'magistrate;' Greek μέγας (mégas, great) produced
'Most' is etymologically unrelated to both 'much' and 'many,' yet serves as the superlative of both. This is called suppletion — the same phenomenon that gives us 'good/better/best' and 'go/went.' Three different ancient roots ('much' from PIE *meǵh₂-, 'many' from