You said you have a manual setup on the glowplugs.
Step on the gas pedal after you turn the ignition to the wait point. But take your foot off before you turn the key all the way to start.
Run your glowplugs longer. At least ten to twelve seconds.
And keep the button pushed in, while you start it. Let go, once it starts. Smooth the idle out with your foot.
No, this is not going to burn your glowplugs up, or blow the tips off of them.
You have a manual system. So you have already eliminated the vast majority of wasted lifetime.
Plus, the factory system keeps turning the plugs on and off for quite a while, after it is started.