Not sure how those are really a whole lot different.
Unless you deliberately heat while “vacuum desiccating”.
“freeze then suck”, vs “suck & it froze” seemed to work equally well in my hands when used to preserve both DNA (tissue) samples & labile secondary metabolites.
Simply placed under vac, my fungal samples were usually frozen in under 10min. Not sure the corn leaves took that long.
one is a hair gentler on your sample.