Based on the description given in the OP, I don't think we have enough information to conclude whether the OP was given the right amount of resources to complet

Based on the description given in the OP, I don't think we have enough information to conclude whether the OP was given the right amount of resources to complete their task or not. While the "migrate to the new deploy infrastructure" might be the most important task from the OPs perspective, there's nothing there to indicate to me that it's a particularly important task from the broader businesses perspective. Indeed, I wouldn't be surprised if this expectation was already communicated to the engineer by their manager, which is why they're here posting about it. Of course, it's entirely possible that you're right, and if this was a more important issue I definitely agree with you that it needs to have a dedicated resource assigned from the deploy team and it needs to be scheduled into their roadmap somehow. Ultimately we're just all speculating based on the small details the OP gave us. However, I think my core point still stands—even if OP is right to feel that the deploy team is making the wrong decision in general about prioritization, they need to at least consider that the deploy team has other, competing priorities that they're juggling, and that the actual change might be more complicated in "at scale" (code review, QA, interaction with other options, documentation, long-term maintenance, etc) then OP is willing to believe.