That's easy to fix:

    Step 1:

    sudo tee /etc/tmpfiles.d/mglru.conf <<EOF
    w-      /sys/kernel/mm/lru_gen/enabled          -       -       -       -       y
    w-      /sys/kernel/mm/lru_gen/min_ttl_ms       -       -       -       -       300
    EOF
    
    Step 2:
    
    
    apt install zram-tools
    sed -i 's/#PERCENT=.*/PERCENT=130/' /etc/default/zramswap

I'm on an older LTS kernel so no support for lru_gen but I will definitely check out zramswap - thanks.

Then also do this:

    echo vm.page-cluster=0 >> /etc/sysctl.d/85-swappiness.conf

> I have an ancient laptop from 2008 with 4GB of ram that runs a modern KDE desktop

Try Alpine Linux, with Xfce which can do most of the same things. Then enable swap compression -- add this to the end of the kernel line in your bootloader:

zswap.enabled=1

This compresses everything going to swap, and decompresses it coming back: less disk reads and writes, and less space used.

Everything gets quicker.

People are saying that 8GB for Android phone is too small. All of those applications are not electron either.

There is bloat everywhere.

4GB still seems excessive, by at least one and probably several orders of magnitude, for what vanilla KDE actually does: browse files, manage windows, and edit text. And KDE is one of the best modern options.

KDE doesn't need 4 GB of ram - that's just what my laptop happens to have which is more than ample to run the OS + KDE + native applications.