Edit: Just realized it is called a lintel. The house is under 2 years old, so I'm guessing it is just surface rust where they did a piss poor job painting it.

Is this rust a potential issue that needs repair? Could it be sanded and repainted?

Sand and repaint.

Is there a certain type of primer and paint I should use?

Thanks! Is there a good way to tell if it's red oxide primer instead of rust? Maybe I just need to add some primer and paint?

You can use a rust reformer rattle can or POR-15 if it's hard to get a sander in there. That's just surface rust, not a big dea

Edit: after zooming in, that's red primer not rust. Just hit it with a bonding primer rattle can and paint to match. You can get a combo bonding primer + paint at Tractor Supply that is better than Rustoleum at Lowes

Edit 2 for below: Yes that's rust. Cover it with a rust reformer. To not paint the brick, you can use a clear instead of colored paint

I see some areas on a lot of my windows and doors that actually do look like rust, so I see the difference now. Is the below type of rust a big issue that needs to be fixed immediately? I heard it can expand as it rusts and cause cracks in the mortar/brick.

JP76 said:

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Pic looks like red oxide primer and not rust but to be sure


Sand

Treat it with Ospho or gem rust killer on the rusted areas

Primer with this

https://www.lowes.com/pd/Rust-Oleum-Stops-Rust-Flat-Black-Spray-Primer-Actual-Net-Contents-10-25-oz/3728555


Or you can use BIN oil base primer


Paint it

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That primer you linked to says you don't need to actually remove all the rust, just brush off anything loose and no need to use a rust remover. Is that good enough?

That rust is not deep into the metal yet. You can scrub it with a wire brush, or use a rust reformer / POR-15. POR-15 might be a bit expensive for the amount you'll use.