You know the thing is I think the pitfalls of Joyce's relationship with Jonathan would be a lot less severe if we knew what they were like before. Like in s1 we have a series of flashbacks of her relationship with Will (partially to make us love Will partly to showcase Joyce's motherhood)
But we don't have that with Jonathan and Joyce. From the jump, we see the parentification. He's helping find her keys, he's making breakfast, he's supposed to know where Will is. And their next big interaction is her admitting that she's checked out as his parent.
But baring one brief moment at the end of the season we don't see them interact outside of this structure. We don't see Joyce interact with Jonathan as her child!
it's been years and it's still genuinely crazy to me that the first two seasons of stranger things had this throughline where all the bad things that were happening in hawkins were directly caused by the us government and that they were excusing the awful things they were doing to their own citizens (children!) through cold war/red scare reactionism. and then in season three there was a secret russian base under the town mall.