Deleting base game content is not the solution to this.
But if the server says it requires DLCs which it actually does not require that would be the real issue

@dedmen the DS does not have the contact (platform) folder:

.\Steam\steamapps\common\Arma 3\Contact\Addons>dir /B
languagemissions_f_contact.ebo
languagemissions_f_contact.ebo.a3c.bisign
language_f_contact.ebo
language_f_contact.ebo.a3c.bisign

Why the A3 launcher can't match AoW correctly though is unclear.

is there any update on a possible fix for this issue?

In T158681#2194277, @dedmen wrote:

Deleting base game content is not the solution to this.
But if the server says it requires DLCs which it actually does not require that would be the real issue

So I just talked to @UDIE about this issue.
The "problem" is, that the contact platform update is present in the list of required mods if you don't own contact DLC.

So basically the solution should be to not list DLCs in the "required mods" window - especially platform updates - at all or make it 100% clear they do not need to be bought if it's not a Contact server ("Optional DLC that can be used" or whatever).

the DS does not have the contact (platform) folder:

"contact" is not "Contact (Platform)"
"Contact (Platform)" is "enoch" folder.

Everyone has Enoch, but if the server uses content from it, it will tell you that you need it (like with other DLCs, place helicopter DLC helicopter in mission file, server will tell you that you need helicopter DLC).

The question here is rather if the server somehow wrongly thinks Enoch content is in use, while in reality it isn't.

I just tested on my own server. It displays I'm missing Contact Platform, and TacOps and Tanks.
When I look into the mission file its currently running, it has "A3_Weapons_F_Enoch" and "A3_Weapons_F_Tank" so that explains two of them... TacOps is indeed weird now :D
So for your case of it saying Enoch is required. Check the mission.sqm of the mission running on the server, search for "Enoch" in it, if you find stuff, then that mission requires/uses Contact Platform content and the Launcher correctly displays that to you.

I have a vietnam server, 6 missionfiles o enoch in them , says i require contact. it will also do this on other servers with no enoch in the missionfile
there is also how every other server requires it in the launcher.
there are however at least 3 places where it will "guide " you to the buy your "missing dlc" page. looks like marketing to me.

also tested on vn server with 0 mission files. just now
says i require contact

In T158681#2268256, @dedmen wrote:

the DS does not have the contact (platform) folder:

"contact" is not "Contact (Platform)"
"Contact (Platform)" is "enoch" folder.

Everyone has Enoch, but if the server uses content from it, it will tell you that you need it (like with other DLCs, place helicopter DLC helicopter in mission file, server will tell you that you need helicopter DLC).

The question here is rather if the server somehow wrongly thinks Enoch content is in use, while in reality it isn't.

The fact remains the client has an Contact folder with the said four files:

languagemissions_f_contact.ebo
languagemissions_f_contact.ebo.a3c.bisign
language_f_contact.ebo
language_f_contact.ebo.a3c.bisign

These are missing in the server distribution (they are also not in the contact modfolder).

With the stricter modmatching check introduced late into A3, this data mismatch should be a problem.