I'm a VSCode user as of a few weeks ago for the same reason. Trying to get React to play nice in emacs, especially when compared to what I got out of the box in VS Code, was an exercise in frustration. Similar problems with Elixir.
I really love spacemacs but I just genuinely don't have time to screw around with my editor constantly, so I ported the bindings I found essential from spacemacs, turned on VS Code's vim emulation, and it's actually been a pretty good experience. It's not perfect, but it's good enough.
rjsx-mode has been around for a few years and handles jsx fine. coupled with prettier mode, I don't have any complaints. have you given those two a try?
I really love spacemacs but I just genuinely don't have time to screw around with my editor constantly, so I ported the bindings I found essential from spacemacs, turned on VS Code's vim emulation, and it's actually been a pretty good experience. It's not perfect, but it's good enough.