The linux dedicated server will not run under the Steam linux runtime
$ steam-run ./ArmaReforgerServer -listScenarios ./ArmaReforgerServer: /steamrt/amd64/usr/lib/x86_64-linux-gnu/libcurl.so.4: version `CURL_OPENSSL_4' not found (required by ./ArmaReforgerServer)
The command steam-run provides a steam runtime environment to the subsequent command.
This is easily reproducible with the Nix package manager or NixOS.
mkdir reforger cd reforger nix-shell -p steamcmd steam-run steamcmd +force_install_dir /home/yourhomedir/reforger +login anonymous anonymous +app_update 1874900 +quit steam-run ./ArmaReforgerServer -listScenarios
The dedicated server is looking for the symbol CURL_OPENSSL_4 in libcurl, but inspection of the steam runtime libcurl shows that it only provides CURL_OPENSSL_3.
The git issue below suggest that perhaps the dedicated server was not compiled against the linux steam runtime:
https://github.com/ValveSoftware/steam-for-linux/issues/6224