The surviving record names individual clergy executions in detail, including Sixtus II, Lawrence and Cyprian, but the 258 edict's own rank-based penalty structure for laity, degradation and confiscation short of death for many, means no ancient or modern historian consulted has reconstructed an aggregate death total across the whole three years of enforcement.
What would resolve this A systematic collation of the named martyrologies and surviving contemporary correspondence, including Cyprian's own letters, across the persecution's three years, of the kind that could establish a documented floor even without a claim to completeness for the wider laity the second edict also targeted.
OpenRoman imperial history; early Christian source criticismPersecution of Christians in the Roman Empire (Wikipedia)