The gap this closes
Most delays on small teams are not backend or frontend problems, they are the negotiation between the two. One person holding both ends means the contract gets settled in an afternoon instead of across three standups and a thread nobody reads.
The stack I move fastest in
Laravel with Inertia or a REST API, React with TypeScript, Tailwind, MySQL or Postgres, queues on Redis, deploys through GitHub Actions. I am comfortable outside that, just slower for the first fortnight, and I will tell you which case you are in.
Where I stop
I am not a designer. I can build faithfully from a Figma file and I have opinions about spacing and states, but if the product needs someone to decide what it should look like, that is a different hire and you should make it.