I think I've found a bug in sort (git branch master). The --reverse flag seems to be ignored when --keys are supplied.

larryp-MBP:bin larry$ ./sort --version
sort (GNU coreutils) 9.1.17-a351f
Copyright (C) 2022 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Mike Haertel and Paul Eggert.
larryp-MBP:bin larry$ ./sort -r <<< $'a\nb'
b
a
larryp-MBP:bin larry$ ./sort -rk1,1 <<< $'a\nb'
a
b

This may be related to a bug reported in February where --version-sort sorted incorrectly.

larryp-MBP:bin larry$ ./sort -Vr <<< $'1\n2'
1
2
larryp-MBP:bin larry$ ./sort -V <<< $'1\n2'
1
2

Current version:

larryp-MBP:bin larry$ sort --version
sort (GNU coreutils) 9.1
Copyright (C) 2022 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Mike Haertel and Paul Eggert.
larryp-MBP:bin larry$ sort -rk1,1 <<< $'a\nb'
b
a

Thanks,
· Larry