Can I sound proof these pipe access holes in a safe manner?

Hi all, I started renting this apartment a little while ago. Recently I’ve been having some issues with noises from the neighbours I’ve been dealing with. Before anyone asks: yes, I talked with them, and it helped quite a bit! Still loud but manageable, so I just want to take some action on my side at this stage if I can.

My unit is heated with these hot water baseboard heaters. The loop seems to be floor-wide. The pipe flowing into my unit comes through a hole in the wall that connects to the bedroom of one of my neighbours. While I can hear bass and such through the wall a little, from my experience the majority of their music/other sounds leaks through this hole (and potentially the other one I linked there stuffed with some sort of foam, presumably from an old heater installation). The wall itself should be solid concrete.

Is it possible to fill this hole with some sort of heat resistant accoustic foam in a safe manner? Or perhaps some other way to seal this off properly? This is an old system, I believe there were heating fins on this side at one point but this length of wall is solely these pipes and the metal shroud covering it now. I obviously don’t want to risk any fire or other damage in doing so. I am a tenant and not an owner, so I am not able to take any permanent measures. If anyone knows what I could do here I would appreciate some advice!