Applied math OR Cognitive Science？Really need advice...

Hi everybody. I'm a junior transfer and international student. Now I have been survived for about half a semester in Applied math major....

Before transferring here I was in Computer Science major and it went fine for me. I'm a kinda example learner. But I found applied math so theoretical and HARD for me(Though it's "Applied math", it has almost the same course requirement as pure math) I prefer and specialize in real applied types of subjects more likely.

So my friend suggested I switch my major to Cog Sci. Tbh, it's my dream major. And it's kind like a combination of Computer Science and neuroscience? I’m super into it.

But I actually plan to do the tech jobs, like SDE/SWE or DA/DS (I did one SDE intern). I'm worried if Cog Sci is not a STEM major at Cal, it will not help me get into the tech field, prevent me from getting into a CS or Robotic master, or influence my OPT length after I graduate.

Really need some advice about majors.........Thank you guys.

Also, I have finished all the lower CS courses and got As. CS61A,B,C and Math 55(CS 70). But at Cal I can't select any upper CS course in Spring/Fall semesters. (That's weird.) I plan to take CS 161 / 169A in summer. Has anybody taken CS in the summer? How are they?