A single partition if we have less than 120GB space, or we could just go with 30GB / and rest home assuming we have at least 60GB.
If we have 120GB space then 40-60G / and the rest home. Swapfile, or systemd swap.
For 240GB+, 60-120GB /, 10GB or 1.5x RAM for swap, rest home.
60GB if they don’t install much, if they have large disks or install a lot then 120GB. 30-40GB may be ok, but that’s for the user to decide.
Obviously the user should be able to change the values.
I have 512GB for my Linux installation:
/dev/nvme0n1p1 2048 206847 204800 100M EFI-System
/dev/nvme0n1p2 206848 239615 32768 16M Microsoft reserviert
/dev/nvme0n1p3 239616 975687028 975447413 465,1G Microsoft Basisdaten
/dev/nvme0n1p4 975687680 976762879 1075200 525M Windows-Wiederherstellungsumgebung
/dev/nvme0n1p5 976762880 977377279 614400 300M EFI-System
/dev/nvme0n1p6 977377280 979474431 2097152 1G Linux-Dateisystem
/dev/nvme0n1p7 979474432 1046583295 67108864 32G Linux Swap
/dev/nvme0n1p8 1046583296 1256298495 209715200 100G Linux-Dateisystem
/dev/nvme0n1p9 1256298496 1885444095 629145600 300G Linux-Dateisystem
/dev/nvme0n1p10 1885444096 1953525134 68081039 32,5G Linux-Dateisystem