Essentially we had deficiencies in our technical interview that allowed for custom-fit preparation, the candidate excelled at selling themselves and negotiating, and there was a breakdown in internal communication where HR was under the impression we wanted to hire at any cost despite us giving the candidate a mediocre rating.
Now we've found they're struggling to do even basic stuff without help and are far from helping others or even taking ownership of minor areas.
They suffer from imposter syndrome (appropriately for once), which further hampers their productivity, communication, and growth as they're reluctant to ask for help with tasks they know should be easy, and equally reluctant to join the efforts of others who might notice their deficiencies.
The result is net-negative productivity. It would probably take another 6-12 months of intense training to get them somewhat productive, and several years to get them closer to the level we hired them at, assuming we can accelerate their learning.
This would require addressing the elephant in the room that they're not at the level we assumed, so that they will understand why we're changing the work mode, accept that learning should be a high priority, and feel permitted to seek more help when they need it. We probably can't reduce the salary, so more productive devs might also be offended if they become aware of it.
Even if we were to successfully address this elephant in the room, they might at some point realize they can't catch up to the level they were hired at without years of dedicated effort and thus quit or "quit internally", making our investment pointless.
I guess in most companies this would be a no-brainer, but we're a small outfit with a focus on personal development, intrinsic motivation, good climate, and low turnover.
Do you think there is any way to rescue this situation? Or should we make this (perhaps justifiably, after their misleading self-presentation) the first time we let someone go for performance reasons?