a tracingmacros roughly around the loading lead to 60000 lines of log in pdflatex and around 8 Millions with lualatex. And a look lead to this comment in the documention/implementation pf `\MT@do@font`: `Execute <#1> ...
resp. 1114111 times for LuaTeX (this is going to be slow, but LuaTeX is slow anyway
– still, there ought to be a better way!)` After `\renewcommand\MT@max@slot{10000}` it was much faster. There really should be a better way, it doesn't make sense to setup whole unicode.