How to evaluate the current company for whether I should switch out of it?

My most popular answer on Taro is on this question! How do I know when it's time to leave a team/company?

But that answer was more geared toward people who had stayed at a company for a significant duration, e.g. 4+ years.

In any job, you should be either learning or earning. It sounds like you're not learning as much in this Goldman Sachs job, either from processes or people. That's a good reason to leave, but you need to be careful:

• 4 months is not a lot of time and you want to avoid being labeled as a job hopper. My thoughts: Perception of being a "job hopper"?
• How much are you earning relative to what you could get in the market?
• Are there opportunities to increase your learning within the company?

The grass is always greener on the other side.

In your situation, you have 2 big things most engineers don't have:

1. A supportive team
2. A name brand (while Goldman Sachs isn't a tech company, it is a globally renowned business overall)

Could things be better? Sure. But given the market and the relatively good situation you're in, I recommend giving your team more of a chance, at least for another 3-6 months. If you still feel like you aren't growing enough, then you can start looking (and hopefully the broader tech market is better at that point). You generally want ~1 year at your first role as anything shorter is a yellow to red flag to recruiters and hiring managers (they will be afraid that you'll just pass the interview, join, and leave soon after).

100% empathize with how slow things are for you though, that's what happens at older companies, especially non-tech ones. It's frustrating, but you can still learn a lot in those environments if you have good teammates. Check out this thread: "Help needed: New grad job going at a slow pace with nothing to do - Next steps?"