I found tutorials how to install it from source, but in all of them the default config is used.
I want to install a new python version, on a different partition than the one where the operating system is, so not in /usr/bin and default paths.
So, in case I revert my main partition from backup, to not be necessary to re-install the new python version. Also to be easy(small changes) to (re)direct an IDE like VisualStudioCode or Pycharm to the new python version.(just add to path maybe).
I prefer not to install a tool to do that.
The process is quite straight forward, let's say you want to install in your $HOME
# 0) Download python source and extracted it to $HOME/tmp/Python3.9.2 directory
# 1)
mkdir $HOME/usr
# 2)
cd $HOME/tmp/Python3.9.2
# 3)
./configure --prefix=$HOME/usr && make
# 4) Now python is built in $HOME/tmp/Python3.9.2, give it a test, then
make install
# Now you should have $HOME/usr/bin/python ready to use.