I think it helps enormously if the designer responsible for the designs understands about the tech used in building it. I don't think that every UX designer needs to be a full stack developer as well, but when you have the ability to actually talk about the tech, you can also translate the design into something that non-design folks might understand.

I often ended up sitting next to one of the developers, working along-side with him, helping him on the technical issues (reading Stackoverflow and github issues on various repos for example) while he helped me with the designs by challenging and testing as we were wireframing ideas. Kinda like aöpair programming, but for designers and less siloed.

Ah yep of course, I’m just pointing out that those kinds of back-and-forths, Figma derived or not, are a sign of a healthy org. A lack of grumbling around miscommunication often means that no communication is happening, not that it’s going swimmingly.