Low FPS for clients on dedicated server

[ShieldNav 0]

Hi! 
Thank you in advance for reading my post. 

So the problem is that players are complaining about low client FPS. And I can't find the reason. I suspect it's a problem with the network engine and desyncs but I can't find where it is exact.

We are seeing a drop of about 10 FPS in clients compared to the "Yet Another ArmA Benchmark" for most clients.

We have a pretty heavily scripted mission. We use ALiVE, ACE, HG Shops, Traffic from Enigma and a small number of other self written scripts. 
I analyzed the mission with Dedmen's ArmA 3 Script Profiler and found nothing critical. Only ACE always in Scheduler with it's scripts and a couple of while{true} runs every few minutes are in the Scheduler all the time. Although I didn't go with Profiling build for server. Don't understand how to use it on serverside.
Here is the Google Drive with the mission if you want to look at it

Regarding the server. We are using a VDS with Ryzen 5950x and 16gb RAM, SSD for storage. Server x64 with the latest Performance build. 1 Gbp/s for download and upload.
Mods for the client:
ArmA 3 Aegis
ArmA 3 Atlas
ACE
CBA_A3
TFAR
The CSAT Modification Project
ALiVE
And our little mod with factions and a couple of textures

On the server side:
ExtDB3 and our server-side database mod.

In the RPT logs there were errors with the network engine, that it failed to send too large a message. I kind of fixed that in basic.cfg but I didn't have enough players to test it yet. 

The server FPS is averaging 40. Using two headless on a remote machine with Xeon via ACE Headless module.

Here is our basic.cfg

// This file has been tuned for a box running only one Arma 3 server on a 
// 1 GBit/s pipe with 64 slots

///////////////////////////////////////////////////////////////////////////////
// Default Options
language = "English";
adapter=-1;
3D_Performance=1;
Resolution_Bpp=32;
Windowed=0;

///////////////////////////////////////////////////////////////////////////////
// Bandwidth Tuning 
// 100MB * 1024 * 1024 = 104857600
MinBandwidth = 104857600;

// Do NOT set this too high or your Arma server will simulate ego-ddos
// 1000MB * 1024 * 1024 = 1048576000
MaxBandwidth = 1200000000;

///////////////////////////////////////////////////////////////////////////////
// Network Tuning 

MaxMsgSend = 1024;
MaxSizeGuaranteed = 512;
MaxSizeNonguaranteed = 192;
MinErrorToSendNear=0.04;
MinErrorToSend=0.004;
MaxCustomFileSize = 122880;

 

All in all, I'm lost. I can't figure out what's causing the clients FPS drop. I tried everything, optimized the mission as best I could so as not to cut the content for players, changed mods from RHS to 2035, played with basic.cfg and tried another machine. Nothing 
I suspect the problem is still somewhere in the crooked settings of the network engine but I need help with that. Thanks!