The doc might not be uptodate if you’re already in Android S (~ 12 ). Just try with recovery and /e/ in S version!
Read this: yesterday I also followed the doc for a S5e (gts4lvwifi). The doc mentions to use the S version. And my uptodate S5e was in Android 11! Because of the S version, I used the recovery-e-1.5.1-s image. I didn’t realize I was about to mix android R and S. And, … and, … It worked fine! 
Reading some responses in this thread, I realise the were some risks? Can anyone explain?