I'm afraid you'll have to get that piece out intact.

I would try getting the intake valve as open as possible and try sucking it out the way it came in with a shop vac.

You'll need to stop up the injector and glow plug holes. A slight inrush of air via the gp hole may be to your benefit however.

If that fails it's prechamber or the whole head time.

Proactive HG replacement may not be a bad thing anyway given the age of the engine.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech