Talou

Hi,
I don't see an advantage installing Tilix valve with or without EGR block but I will need to explain it further.
The problem exists somewhere else. If you wish to maintain EGR as is then there is no point hacking boost control system because EGR will not function until boost pressure drops off (exhaust fumes pressure can't push back against turbo) That's why ECU will back off boost first then open EGR.
While EGR cools combustion temperature that is not done because or to lower catalyst temperature, there is nothing in the control system to monitor that part, system fully dumb hoping for the best....
What Tilix valve alone does is just limits max boost while giving max spool up rate which will create several problems to contend with as ECU will have no ability to control those and as such will have only one option left and that is to introduce those dreaded limps or fuel cuts. Max 10.5 psi at give TPS position and RPM until you reset the air flow (MAF volume) by letting go of the go pedal.
Higher boost creates higher air flow so what to do?  If you decide to keep ECU boost control and adding Tilix to the mix you're just wasting your money and effort as that achieves zilch.
Unfortunately the only thing left is combination of needle valve (very conservatively set to slow down spool up rate) Tilix set at max 17-18 psi and then fingers crossed to avoid fuel cut is to learn when to keep acc pedal not pressed down too long as RPM climb up.
You will be affected by cold weather, hot weather you name it. No amount of fiddling will fix it.
Because the fuel maps are set in the ECU to keep emissions low ECU will respond by limiting fueling the moment its predetermined limits are breached. It is hopeless struggle.
The only fix is to re-map the ECU, then you stop worrying about installing Tilix or anything else.
EGR is not opening every time, only under certain conditions like TPS position, MAF airflow, RPM etc.
It usually opens during a cruise (steady TPS) and not under acceleration. That's why those dreaded scenarios cruising on the highway boost is backed off, EGR opens, exhaust temps raise so the catalyst can do its work and everything is cooking in the meantime especially if the injectors are over fueling as well it becomes rich mixture and that is the end of the diesel engine.