You wouldn't like it if said company kept surprising you with new contract terms every time you've agreed on something. Especially in this stage of your relationship, it's best to be transparent and open about your requests.
There's also an added benefit to this transparancy; if the company is unable to meet one of your requests, let's say there's a ...
Is it okay to negotiate salary and remote work at the same time?
TL;DR: Is is OK and it is expected.
Think about this: in the job offer, if the organization mentioned only one responsibility and after accepting the offer, they tell you about another responsibility, and after joining, they tell you about several more - how would you feel?
Put all terms and ...
Negotiate for everything you want at the start.
It's best to lay your cards on the table so everyone knows what is happening, no surprises further down the line. That just makes you look like you didn't think things through seriously, which is unprofessional.
I am also considering leaving the company because of this reason
Excellent answers already, I upvoted all three. But I don't use any of these strategies, I let others pop their heads up for the group efforts and will watch in interest if they get their heads chopped off or quite happily take any benefits gratefully. There is another angle.
Unfairness to ...
I'd like to complain to the management about this unfairness without
naming people, because unfairness breeds resentment. Is that advisable
It sounds like you already did complain ("I mentioned the above arguments also, but my request was still rejected.") but it didn't get you anywhere.
Repeated complaints aren't advisable.
What is the best way ...
Unless remote working provisions are built into your employment contract I would be inclined to tread carefully.
I've dealt with several companies whose workforce are predominantly remote workers however they've tended to be in the consulting space where collaboration between employees (on internal company objectives) seemed rare. Most employees were "...
They are most likely trying to get more people to the office by following a policy of "let's not drive away old timers by taking away their remote time but let's also not allow people who normally work at the office to start going remote"
It's not about fairness, it's about strategic goals. Upper management could be more aggressive and risk senior people ...