You are listing a setup for a SERVER and one that has long ago been abandoned.
- no swap, we use a swap file
- /tmp and /efi are not for you to setup; the installer takes care of it. /var only if you use a server and even then there are better option: you edit mysql conf and log conf to use your data partition and not
/var/ (you want to keep those files after a re-install anyways).
The only one you need is a data partition: so / for --a minimum-- of 25Gb (add a few if you want) and the remainder as a named partition (I called mine /discworld/, You can use NTFS -if- you have a dual boot; otherwise stick to EXT4).
Edit ~/config/users-dirs.dirs to point to the partition, Then "move" the directories in /home/$USER/ to /discworld/.
This has nothing to do with speed but with convenience:
- easy backup of personal files
- re-install means formatting
/ and mounting your data partition.
So during the installation in the create new partition menu. Define a partition mounted at / and ext4. Then a second partition e.g. mounted on /home or /jim?
I would use /jim myself and keep /home/ on / and empty except for the hidden (/config) files in there . You can use /home but that has to be ext4 so if you have another OS (ie. Windows) you can not see those files.
Why only 25GB for /?
For a desktop this is more than enough, You will not reach 20.
Can I use e.g. 100GB instead?
Sure. You can always change it using gparted the shrink and enlarge options.
Edit ~/config/users-dirs.dirs to point to the partition... is this something to do after the installation?
Afterwards.
Examples from my system with all the fluff removed:
rinzwind@discworld:~$ df -H
Filesystem Size Used Avail Use% Mrun
/dev/nvme0n1p2 41G 17G 23G 43% /
/dev/nvme0n1p3 462G 275G 164G 63% /discworld
(17G is due to using snap but in all my years it never went over 20Gb; I always check just before reinstalling to a new version)
and
inzwind@discworld:~$ more .config/user-dirs.dirs
# This file is written by xdg-user-dirs-update
# If you want to change or add directories, just edit the line you're
# interested in. All local changes will be retained on the next run.
# Format is XDG_xxx_DIR="/discworld/yyy", where yyy is a shell-escaped
# homedir-relative path, or XDG_xxx_DIR="/yyy", where /yyy is an
# absolute path. No other format is supported.
#
XDG_DESKTOP_DIR="/discworld/Desktop"
XDG_DOWNLOAD_DIR="/discworld/Downloads"
XDG_TEMPLATES_DIR="/discworld/Templates"
XDG_PUBLICSHARE_DIR="/discworld/Public"
XDG_DOCUMENTS_DIR="/discworld/Documents"
XDG_MUSIC_DIR="/discworld/Music"
XDG_PICTURES_DIR="/discworld/Pictures"
XDG_VIDEOS_DIR="/discworld/Videos"
Also: the smart thing to do is to add all alterations you do into a textfile or copy files to your own partiton. If you do that you follow up a re-install by executing that text file and the system itself sets itself up (instead of you editing the same files every 6 months ;))