It seems that there are some issues with tlmgr update

[Guy-Bart Stan]

When I run tlmgr update --all, this is what I get:

sudo tlmgr update --all
tlmgr: package repository 
http://mirrors.rit.edu/CTAN/systems/texlive/tlnet (verified)
===============================================================================
tlmgr itself needs to be updated.
Please do this via either
   tlmgr update --self
or by getting the latest updater for Unix-ish systems:
http://mirror.ctan.org/systems/texlive/tlnet/update-tlmgr-latest.sh
and/or Windows systems:
http://mirror.ctan.org/systems/texlive/tlnet/update-tlmgr-latest.exe
Then continue with other updates as usual.
===============================================================================
tlmgr: An error has occurred. See above messages. Exiting.


Doing sudo tlmgr update --self doesn't update anything though.

sudo tlmgr update --self

tlmgr: package repository 
http://mirrors.ibiblio.org/pub/mirrors/CTAN/systems/texlive/tlnet (verified)
tlmgr: saving backups to /usr/local/texlive/2020/tlpkg/backups
tlmgr: no self-updates for tlmgr available.


Am I really supposed to download update-tlmgr-latest.sh from 
http://mirror.ctan.org/systems/texlive/tlnet/update-tlmgr-latest.sh?

Shouldn't sudo tlmgr update --self do the necessary self-update?