A custom android OS for those two specific models producted for USA and China only, could be never released.
- SM-G991UZVAXAA
- SM-F711UZGAXAA
Versions: SM-G991B, SM-G991B/DS (International); SM-G991U (USA); SM-G991U1 (USA unlocked);
Since the Galaxy s6 you need international model to use Custom OS.
Better buying a
Samsung Galaxy s10 5g international SM-G977B ( beyondx )
for /e/ official support…
https://doc.e.foundation/devices/beyondx
or envisage installing a G.S.I. ( only with unlocked bootloader witch is not you case )
https://m.gsmarena.com/compare.php3?idPhone1=10626&idPhone2=9588
But according to voLTE issue, Samsung are not adapted to use in the USA better choose another brand like MOTOROLA or Teracube 2e
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- List of Officialy Supported devices (up to date)
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- List of Official upgrade Test builds (from year 2020)
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