Ubuntu server doesn't recognize Ethernet connection in netplan configuration [closed]

I'm very new to Ubuntu, Linux, Netplan, and using my terminal at all. I'm running an Ubuntu 24.04 server on a Raspberry Pi 5, which is hooked up to Ethernet via cable.

According to >ip a, The device is connected to Ethernet.After running >ip a

It's also connected to WiFi. The server's Netplan configuration file (/etc/netplan/50-cloud-init.yaml) doesn't seem to notice that there's Ethernet, and doesn't look like any of the pictures of Netplan config files I see online.

Example of what I think my config file SHOULD look like:

network:    version: 2    renderer: networkd    ethernets:        enp3s0:            dhcp4: true

Note: I don't really know what's dangerous info to share, so I just covered anything that looked sketchy in the images.

I'm trying to set up a static IP, but I'm having trouble as the config doesn't look like any config in any of the tutorials I see, most notably in that it has no reference to Ethernet, so there's nowhere to define an address. Other than this, the server works fine.

What my config file currently looks like:

network:    version: 2    wifis:        renderer: networkd        wlan0:            access-points:                fishnet:    #wifi network name                    password: [redacted]            dhcp4: true            optional: true

I've tried manually changing the file to look like the ones I see online, just adding an addresses spot in the wifis and wlan0 sections, rebooting the server, unplugging/replugging the Ethernet cable, running a completely new instance of Ubuntu on a different SD card (and all of the above on that new instance). None have produced a result other than disconnecting my ssh.

My end goal is to establish a static IP for this server. How can I get my Netplan configuration file to look like the ones I see online?