You describe the toxicity I have experienced working in the product team vs a platform team.

If you don't find it interesting to build products with whatever tool is most adequate (excel some times) maybe you should not work at a company building products. At least you should understand that you are part of the support team not the main guy.

And yes, moving to GitHub from Jenkins is maybe objectively a good choice. But if it stalls product development for 6 months, is that objectively-objectively a smart move? It could of course be, but it requires more situational awareness than "is this tool better".