The irony is that these companies will make you sign & enrol trainings for "code-of-ethics" and the same management will indulge into shady practices (like the OP mentioned). Btw, there are other ways to get rid of employees which do not even need PIP.

I have made peace with the fact employees are just means to an end. Always have been. Nothing less or nothing more. The power is extremely lopsided in favour of the companies. This makes so many things beyond the control of an individual [1]. Focus on things in your control:

1. Keep learning

2. Be debt free as soon as possible.

3. Invest and build a financial cushion

4. Eat healthy and exercise (I am pretty bad at this but trying to improve)

5. Develop an alternative skill(s) which can you put to use if needed

6. Never burn the bridges, no matter what.

All of the above are easier said than done but I see no sustainable way of coping up.

[1] My current employer (which is a listed company) got acquired by a private equity. I have no idea what will happen but I am relaxed.

My advice to protect yourself is just the usual - "manage up". Build a good relationship with your manager (and preferably their manager) and do what you can to confirm that the work you're doing is seen as impactful to their goals. It won't 100% protect you, as sometimes there are circumstances outside their control too, but if you have a good relationship, they will fight to keep you.

Very common.

Your career is 90% politics and 10% skills. Junior devs enter the field thinking this is meritocracy but it is not. Until they realize the truth, their egos will keep getting hurt.