Exchange2019-KB5074993

That SU is not publicly available. See https://support.microsoft.com/en-us/topic/description-of-the-security-update-for-microsoft-exchange-server-2019-cu15-february-10-2026-kb5074993-8a7f2e49-2f91-4c18-a1c6-959ac7e2b1dd for information on how you can obtain it.  Basically, you'll need to sign up for ESU Period 2 (see Announcing Period 2 Exchange 2016/2019 Extended Security Update (ESU) program | Microsoft Community Hub) and then request the SU.