Did Titus Actually Use Captives from Yashar'al as Human Entertainment After the War?
Primary: Josephus, The Jewish War Book 7, Ch. 2–3 · After the fall of Yahrushalam · Commander: Titus
What the ancient record says
Titus traveled through cities staging public spectacles; captives from the defeated population were used. At Caesarea Philippi large numbers of captives were killed, some thrown to wild animals, others forced to fight one another (not battlefield deaths, captives).
At Caesarea, celebrating brother Domitian's birthday, more than 2,500 captives killed (fighting wild animals, being burned, forced to fight each other). At Berytus, celebrating his father's birthday with greater magnificence, captives again killed in similar spectacles.
Josephus explicitly connects the deaths with the birthday celebrations. The 2,500+ number stays attributed to Josephus; the event itself is directly attested.
Read it for yourself. Josephus, The Jewish War 7.2–3.
Evidence strength: Very strong primary ancient testimony. Documented in Josephus: captives used in spectacles; killed by wild animals; burned; forced to fight. Reported number: 2,500+ at Domitian's celebration.