Included here are five different packages for Raspberry Pi Ubuntu.
If you have an RPi4 your best option is one of these three depending on if you run Focal LTS or Jammy LTS, or Kinetic:
linux-raspi-focal-5.4.0-arm64-23.02.28.zip
linux-raspi-jammy-5.15.0-arm64-23.02.28.zip
linux-raspi-kinetic-5.19.0-arm64-23-02-28.zip
If you have an RPi2, RPi3, or low RAM RPi4 your best option is:
linux-raspi-jammy-5.15.0-armhf-nolpae-23.03.28.zip
If you want to run a 32bit kernel on RPi4 your best option is:
linux-raspi-focal-5.4.0-armhf-23.03.28.zip
linux-raspi-jammy-5.15.0-armhf-23.03.28.zip
Note RPi4 will run any of the above packages. My suggestions are only that. RPi2 requires 32bit. RPi3 can run 64bit but there is little point. You should not use the nolpae kernel on an RPi4 with greater than 2GB ram, 2GB is the max.
To install download the packages to /tmp/, then unzip them, then:
sudo dpkg -i linux*deb
If you desire the tools packages they are provided by themselves to download. Download the pair that matches your selected kernel. The tools are not required.