I know you have been having trouble packaging Pi-Hole, I've seen the request for pi hole has been open since 2016.

This is an alternative to pi hole but pretty much does the same stuff.

Maybe this could be easily packaged instead? I don't know.

I gave it a quick shot but because port 53 for DNS is a privileged port it's not possible anymore, Synology has put in roadblocks to prevent package developers from using root. Using a different port than 53 is worthless but even that wasn't possible, not sure why, in the config file I specified an unprivileged port:
https://adguard-dns.io/kb/adguard-home/getting-started/#running-without-superuser

https://help.synology.com/developer-guide/privilege/preface.html

You can still use docker, however.

Even the sample capabilities give the above error message
https://help.synology.com/developer-guide/privilege/privilege_config.html

{
    "defaults": {
        "run-as": "package"
    },
    "username": "sc-adguardhome",
    "tool": [{
        "relpath": "bin/adguardhome",
        "user": "package",
        "group": "package",
        "capabilities": "cap_net_raw",
        "permission": "0700"
    }]
}

{
    "defaults": {
        "run-as": "package"
    },
    "username": "sc-adguardhome",
    "tool": [{
        "relpath": "bin/adguardhome",
        "user": "package",
        "group": "package",
        "capabilities": "",  #< even an empty string is blocked, but if i remove this line, I can at least install the package
        "permission": "0700"
    }]
}

Source Code if anyone is interested: master...publicarray:spksrc:adguardhome