It's one thing to do this to learn more about software development, it's another to give it a name and a website.
They're really leaning into the "I'm just an intern without commercial intents" narrative, but regardless of their intent, it's still incredibly unethical to create something similar your previous employer's IP and market it independently.
Honestly Airtable is the future, I'm very excited to watch it grow. 90% of software I create for enterprise companies is just spreadsheets on the cloud.
I love Vue for its flexibility. You can write functional components with explicit dependencies, scoped CSS, and no state. OR you can just drop a CDN file on your webpage and have a bunch of global components.
To me, it's one of the easiest frameworks to teach and maintain.
While I believe React is technically a more correct way to write applications, it can be very heavy-handed. Vue is a great compromise for mixed front-end / full-stack teams.