I am a senior front-end developer who wants to change technical focus - considering c++ or Swift. What should I choose?

[Mikey]

Hi all, I would like to ask you a little problem that has been in my head for a while, and I can not find an answer, i am a senior front-end developer who wants to change technical focus - considering c++ or swift. what should i choose? Help me a lot, thank you very much for informing me as soon as possible.