You know you can comment on the mod page itself and not on every new uploaded version right? You can edit the initial post with the changelog as you update it and change the "game" field in the mod json to point to the new version of what you've uploaded.

No uploading as a map is how you do it, what you can do instead of commenting on each new map upload is to just comment on the lobby settings part with the changelog, and update the mod JSON to point to the new map versions.

What you can do is change the mod JSON on the site (in your case, here: https://zero-k.info/Mods/Detail/188 ) to something like the below (taken from my mod, an attempt at fixing Arean Mod which is ironically very broken), and replace the relevant fields with ones more appropriate to your mod.

{
    "name" : "Arena Mod Bugfix",
    "description" : "Use an HQ building to spawn units and defeat your enemy",
    "roomType" : "Team",
    "game" : "Arena Mod Bugfix v1.0.0",
    "options" : {
        "terrarestoreonly" : true
    }
}

Of particular note is the "game" field. You can just update that field whenever you upload a new version. Therefore you don't have to comment on each new version and instead you can just make a new comment on the mod page itself. It also means that when someone selects your mod in the lobby it automatically applies both the modoptions and changes it to your mod instead of base Zero-K.