I honestly thought coming from Valve it was gonna be something better but it's plain terrible. The launcher uses a ridiculous amount of resources for apparently no reason because the UI isn't *that* complex to justify almost 1GB memory usage, every and I mean EVERY game you download gets you thru DirectX and vcredist installations even if you already have them installed, and the best: you have to PAY to be able to add friends?! LOL. Someone else may know more about the search quirks on battle metrics, but when in doubt that always seems to work for me.I tried this platform and I can only say it SUCKS. Two caveats - First is, the mod list isn't always/usually perfect, but I think it will be highly accurate for your purposes of, "is this server running mods yes/no?" Second I've found some wonkiness with their search function, if you're having trouble looking up the server you're interested in, make sure you are searching for the EXACT server name, capitalization and characters included. You can even join straight from battle metrics and skip the join system in Ark altogether.
You simply need to check that there are no mods running (or that you're okay with the mods that are running), it even links to the mods steam page so you can see what things are. For any server you're thinking of trying, look it up on, mods used are listed on the server's specific page, and frankly a ton of other info I find helpful when deciding on a new server to play. However there's a pretty good work around in your case that just requires a little extra effort. Agreed Arks join system is ridiculous, but I don't think even makes the top 50 list of fixes the game needs.
Okay, so what you really want to achieve then is understanding which servers are running mods, and which servers are not running mods.