I just installed TeXLive 2021 on a Windows 10 system where TL2020 was installed. The installation was slow but went well. Once it was done, I clicked too fast on the last dialog box that may have had some instructions to update the path.
kpsewhich --var-value=TEXMFROOT still returns C:/texlive/2020, instead of C:/texlive/2021. The TL manager gui does show the 2021 folder but anything on command line points to 2020. One consequence is that when I tried adding the tlcontrib RSA key, the key was installed to the 2020 folder, and the only way to have it in the right folder was to input the full path to tlmgr.
I checked the Windows environment variables and there is no TeX-related variable. Where does one update that default folder so the right version is called?