Lua's mw.language:formatDate shouldn't have the same 6000 characters limit that ParserFunction's #time has, since the Lua scripts are already limited in the duration of script execution and memory consumption.
[Forwarding for Paweł Ziemian per https://www.mediawiki.org/wiki/Thread:Extension_talk:Scribunto/Limits_of_mw.language:formatDate .]
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