"I became dead" — why Revelation 1:18 proves Jesus is not Jehovah

Revelation 1:17-18: "I am the First and the Last... and I became dead, but look! I am living forever." Jehovah is immortal — he cannot die (1 Timothy 1:17). Jesus became dead. He cannot be Jehovah. "First" = first resurrected to immortal spirit life (Acts 26:23; Col 1:18). "Last" = last sacrifice ever needed (Hebrews 7:27; 10:12). The keys are GIVEN (delegated authority), not inherent. Compare Isaiah 44:6 where Jehovah uses the same title in reference to his eternal self-existence (no beginning, no end). Do these two uses of "First and Last" have the same meaning? nwtprogress.com