As for the hiring process, learn software tools in depth. Some are free, but don't hesitate to pay monthly if the price is reasonable. You can put an online class certification on a resume. This holds more weight than just listing it as "X with Y years experience," even if it's from a no-name institution. Your resume needs to glitter and sparkle nowadays. Your first big barrier to overcome is now third party recruiters, which know absolutely nothing. Then it's HR, who also know absolutely nothing. Then it's high level managers, then some assessment tests, and then your competency and character will be finally enter play in the hiring process. Should also add: throwing in keywords for the ATS and getting your resume professionally read isn't clever. Everyone else already does this.
For salary, what you see on glassdoor will not be offered until your 30's. There's a strong downward push on salaries in almost any STEM industry, as those in STEM are usually agile enough to switch skillsets quickly for in-demand positions (or the companies just hire globally from infinite poeple). Most engineering colleagues I know started off underemployed with 60% of industry standard pay in a stepping stone position after an extensive job search. I did not, but I would attribute this to a moment of wild luck (as well as spending a few thousand dollars and six months working for free).
Consider joining makerspaces and makerfairs. Not all are good. If it's just a room of 3D printers, it's not the best. This is a good networking spot. Projects you do there are small potatoes, but are actually hands on with real freedom. Enjoy it while you can. Idk what zoomers do. If not this, then find its equivalent.
Posting proof of software skills on social media is smart. I'm not sure what EEs use these days, but a good example for MEs would be to create an over the top or engine in CAD that runs well and post it on Instagram. For optics, simulating how light bounces around in a triptych or doing ray tracing for jewels in famous royal crowns works. Something flashy that proves you can use the tools you don't need training.
Daily life is usually in front of a computer in an open office. The manufacturing or applications portion will likely be in another country. Get good at ticking manager checkboxes. Performance specifications or bugs will be emailed to you by another department. Your weekly assignments will usually be data driven. There will likely be an AGILE workflow. You may only see the product a few times ever in select meetings. These jobs usually require some travel, especially for new hires touring the HQ. Have an international passport up to date.
Pick ambitious friends in university with a loyal spirit and keep them close. You will rely on each other for employment during the next ten years. If you get a connection, get one of them in on it and share resources. The industry is too competitive to be an individual. At least two friends should come from upper-middle class backgrounds with wealthy parents. Don't be shy, they know what's up and will help you out if they like you (as someone else also carried their parents up back in the day). If you're paying for software or it's hard to setup, host a server and let them (and only them) join to use it for free.
Can you join some kind of diversity program at your university? Even if you're not a diverse female, can you still somehow get in and leave with a leadership position for your resume? This significantly boosts you and may be, today, the single most important factor in getting hired for big companies. I've lisened to managers vent about getting scolding meetings with HR multiple times because the company is demanding diveristy be hired. No explanation is good enough for HR. They will keep the posting up longer than it needs to be and add extra hiring steps in order to raise the chances of one of these applicants appearing. The minute a diverse / female engineer shows up, they get an opportunity no matter what skill level they have. If the job requires real skill then the company will gladly pay for a second engineer to get hired, but the second guy needs to be extra skilled to compensate for the other hire. You will at some point get ghosted and find out your dream job was given to a woman with less engineering experience than your girlfiend (been there).
Lots of people are complaining about this, and I've personally seen this practice happen at my old job. They eventually pressured my manager to go to a segregated job fair to get that diveristy. The new hire never caught on, almost killed two of us (no, she didn't get fired), more than doubled our workload, and someone very skilled needed to be hired to take the pressure off of us. Is there a way to pretend you're hispanic or arabic, possibly trans? If so, try it. If you pay a $140 fee, you can renew your passport with a different gender on it. No questions asked. I personally got stuck at this barrier really hard where I used to live. It took over two years of sporadic work and above-average ghosting rates from recruiters to realize what was happening, especially when every important institution was telling me the exact opposite was happening. It led to a long gap in my resume / experience that I never recovered from (on top of other misfortunes).
Today, I struggle to find steady work and have strongly considered dropping STEM altogether. When I do get work, it pays very well, top 10% income for my age bracket, but it's finished in less than a year and then it's back to the never-ending job search and depleting my savings.
I'm honestly not sure how to give advice here. The more the economy and culture change in this direction, the more the average person loses agency. I recognize that good advice from just ten years ago will today lead you on a wild goose chase. I don't think it's right to give younger people the impression that bad outcomes are always preventable with enough willpower. If it's cheaper to lay off EEs and open an office in Malaysia, they're going to just do it. And having a six pack won't save you. Most often the case, the ones who made that decision will be people you have no access to.
The older gens don't understand this and will feed the younger gens bad advice. Or, more commonly, just blame them for society-wide misfortunes. "Of course Merk will fire all their contractors each year to rehire college grads and oversaturate the industry! It's your own fault for being unemployed because you started a degree in biochemistry when the field was in demand! You idiot!" etc.