It's a very fair question, since the debate about Carthaginian/Punic child sacrifice is an old one. In the Old Testament, where Phoenicians (Levantine ancestors of the Punic people) are referred to as Canaanites, more than two dozen passages describe some kind of sacrificial killing of offspring with fire. Roman writers like Plutarch and Diodorus Siculus also referenced the practice. Obviously, the inherent bias to these accounts makes them problematic.

However, archeological evidence from Carthage and other Mediterranean cities under Punic influence (such as Malta and Nora) do point toward a grain of truth in the historical accounts, however politically motivated and exaggerated they may be. The burned remains of young children have been found in several sanctuaries (still generally referred to by the Biblical Hebrew term of 'tophet'). These remains are consistently accompanied by standard, formulaic inscriptions on stelae (stone grave markers) stating that a god granted a favour to a particular person. Based on this evidence, Paolo Xella has a detailed hypothesis on how Carthaginian/Punic child sacrifice could have plausibly happened. It is worth noting that not every Punic city seems to have had a tophet, and the debate over Punic ritual child sacrifice is by no means settled.

The book I'm referencing is "The Tophet in the Ancient Mediterranean" ed. by Paolo Xella, but I am having a hard time finding enough info on it to cite it correctly here. Individual chapters of it can be read on academia.edu after making a free account.