I was very impressed with Linux Lite. The name is terrible, but the distro has worked great. It uses the Ubuntu 18.04 standard apt repos. Since I replaced the kernel, my presumption is most of the benefit is just selecting a smaller subset of default packages to install.

https://www.linuxliteos.com/

Installation on a machine with 2Gb RAM resulted in a system that works just fine, for running scripts, compiling medium-sized projects, running web browsers, media playback, etc -- all on a credit-card sized machine.

The desktop is based on XFCE. The post-installation steps I took are listed below.

    # emable swap to compressed RAM
    sudo apt-get install zram-config
    
    # log to RAM for speed, less wear on eMMC
    echo "deb http://packages.azlux.fr/debian/ buster main" | sudo tee /etc/apt/sources.list.d/azlux.list
    wget -qO - https://azlux.fr/repo.gpg.key | sudo apt-key add -
    apt update
    apt install log2ram
    
    # remove icon generator that hogs machine
    sudo apt remove --purge tumbler
    
    # remove powerline garbage
    sudo apt remove --purge powerline
    
    
    # Liquorix kernel, see https://liquorix.net/
    sudo add-apt-repository ppa:damentz/liquorix && sudo apt-get update
    sudo apt-get install linux-image-liquorix-amd64 linux-headers-liquorix-amd64
    ## NEEDS linux-firmware from focal distro
    ## see https://packages.ubuntu.com/focal/all/linux-firmware/download 
    ## for latest link
    wget http://mirrors.kernel.org/ubuntu/pool/main/l/linux-firmware/linux-firmware_1.187_all.deb
    sudo dpkg -i  linux-firmware_1.187_all.deb
    rm linux-firmware_1.187_all.deb
    
    sudo apt install powertop iotop
    
    # fix font rendering
    cat <<'EOF' > ~/.fonts.conf
    <!-- disable embedded bitmaps in fonts to fix Calibri, Cambria, etc. -->
    <match target="font">
       <edit mode="assign" name="embeddedbitmap"><bool>false</bool></edit>
    </match>
    EOF
    
    
    # remove spectre mitigations, make computer fast again
    sudo perl -pi.bk -e 's|splash"|splash mitigations=off"|' /etc/default/grub
    sudo update-grub
    
    # disable and completely remove AppArmor and snapd
    # https://www.simplified.guide/ubuntu/remove-apparmor
    sudo systemctl stop apparmor
    sudo systemctl disable apparmor
    sudo apt remove --purge apparmor snapd
    
    
    # suppress this language related updates from apt-get
    echo 'Acquire::Languages "none";' | sudo  tee -a /etc/apt/apt.conf.d/00aptitude
    
    # remove irqbalance 
    # see https://github.com/konkor/cpufreq/issues/48
    sudo apt remove --purge irqbalance