Can you add the Builds of ProtocolLib? (Found on their spigot page)

The dev builds aren't available on spigotmc.org, so no.

There's a workaround I found:

(Assuming your server isn't cracked)

1. Enable Cracked in https://aternos.org/options

2. Install the OpeNLogin plugin

3. Restart/Start the server

4. When you join the server, it'll ask you to choose a login plugin, either nLogin or OpeNLogin

5. Click on nLogin

at

6. The server will install the latest dev build of ProtocolLib for your Minecraft version on the next start

7. Delete nCore, nLogin, nLogin.jar and OpeNLogin from your plugins folder

8. Disable Cracked in https://aternos.org/options

..Just try it and see.

I think it should install the dev build for 1.19.2.