My subset suggestions. I have seen none of these (that's how I roll with subset suggestions), so if anyone thinks one or more don't fit the themes given, do speak up.
Autopsy (1975) [tt0073327] - Giallo ~ Women ~ Flashback
Edge of the Knife (2018) [tt8947034] - Folk ~ Passport (Canada)
The film is in an endangered language (Haida) and was created primarily by indigenous people. It's not labeled as horror everywhere, but it is in the folk horror doc and part of Shudder's collection.
The Last Winter (2006) [tt0454864] - Trek ~ Cosmic
Berberian Sound Studio (2012) [tt1833844] - Synth ~ Psychological
Night of the Lepus (1972) [tt0069005] - Joe Bob ~ Trek ~ Frightfest (Monster) ~ Chronological
The Call of Cthulhu (2005) [tt0478988] - Cosmic ~ Flashback
The 4th Man (1983) [tt0086543] - Writers ~ Giallo ~ Psychological
Fiend Without a Face (1958) [tt0050393] - Frightfest (Monster) ~ Body Horror ~ Flashback
Dearest Sister (2016) [tt4701908] - Frightfest (Ghost) ~ Folk ~ Passport (Laos)
Excision (2012) [tt1984153] - Body Horror ~ Trek ~ Psychological ~ Sleazoid (Porn Stars) ~ Flashback
Island of Lost Souls (1932) [tt0024188] - Mashup (Parks) ~ Frightfest (Monster) ~ Body Horror
The Belko Experiment (2016) [tt1082807] - Mashup (High Rise) ~ Trek ~ Synth
The Uncanny (1977) [tt0076853] - Anthologies ~ Writers
Trouble Every Day (2001) [tt0204700] - Sleazoid (Erotic) ~ Psychological ~ Body Horror ~ Vampires ~ Women
Salome (1922) [tt0013571] - Chronological
The Inheritance (1947) [tt0039492] - Chronological
The Stone Tape (1972) [tt0069316] - Chronological ~ Folk ~ Frightfest (Ghost)
Office Killer (1997) [tt0119819] - Chronological ~ Slashers ~ Flashback
Pretty slim pickings for 1922 -- makes me wish we hadn't burned off Nosferatu as the very first subset pick.

That said, since I know it's hard to get complete sets of four suggestions from people for this theme, and since some people will likely have multiple picks on the subset list anyway, I'll just float the idea that Chad should feel free to pick and choose from everyone's chronologically relevant suggestions if needed -- one person's 1922 suggestion, another's 1947, etc.
Saloum (2021) [tt10756184] - Passport (Senegal)
This looks to be the first horror film ever to come out of Senegal! It was well-received at festivals last year, and it's coming to Shudder in September.
Footprints on the Moon (1975) [tt0071950] - Women ~ Giallo ~ Flashback
This is in the House of Psychotic Women box set, but it's also available outside of that, sometimes under the name Primal Impulse. Both Footprints and The Other Side of the Underneath are discussed in the book, but the latter seems less available, and also from the description I think would likely be... divisive at best.

(The other two aren't in the 2012 book at all, but maybe they're in the updated version.)
The Black Phone (2021) [tt7144666] - Telephone ~ Slashers
The Witch Who Came from the Sea (1976) [tt0075433] - Demonic ~ Psychological ~ Women ~ Flashback
Pet Sematary II (1992) [tt0105128] - Halloween ~ Sleazoid (Porn Stars) ~ Zombies