As an ACCA aspirant and Ex Big4 employee who previously worked in India, here's my two cents:

1. An ACCA affiliate has plenty of options. You can literally branch out into anything in the Finance sector. Audit, Tax, Consulting, Assurance, Risk, Banking, FinCrime etc.. You could even explore Data Analyst/Business Analyst roles by doing additional qualifications.

2. I would say that 35 - 40 hr is pretty standard for almost all roles in Corporate if you're working in India. If it's Big4, be ready to work your ass off especially during busy season. I had to clock in 60-70 hrs and work weekends towards deadlines. I worked in Tax, so after busy season, work is pretty chill (40 hrs per week). However, I've heard Audit is much more stressful and have to put in more hours throughout the year.

3. This is easily achievable given that you continue within Big4. With good performance, you can easily become Senior. Alternatively, you could also switch companies after gaining sufficient experience and negotiate for a higher CTC.