BCA

Yes, you can get admission in MCA without Math in class 12th, because you have completed BCA, so don't worry you can apply.

In this course, Maths is compulsory for BCA in Jamia Hamdarad University.

Yes, you can apply for an MS abroad after completing BCA. You may be required to appear for the GRE and also appear for a language proficiency test, to qualify for an MS course abroad. Please check for precise requirement at college website, as different colleges may have different requirements. Regards.

Top BCA Colleges in Bangalore are mentioned at the link provided below. This ranking is based on college rankings published by India Today. https://www.shiksha.com/it-software/ranking/top-bca-colleges-in-bangalore/96-2-0-278-0.

Top BCA Colleges in Delhi/NCR are mentioned at the link provided below. This ranking is based on college rankings published by India Today. https://www.shiksha.com/it-software/ranking/top-bca-colleges-in-delhi/ncr/96-2-0-10223-0.

ACMS, IMS, Techno India, FIEM and few more colleges are best for BCA in Kolkata. BCA fee vary from college to college.

If you have good knowledge of Programming Languages, so you must apply for the post of Software Developer or Web Developer, as well as I would suggest you to Learn the Digital Marketing course in which we get 100% Placement assistance.

MCA graduates are paid up to INR 3.5 Lacs per annum in the private sector. The Indian graduates in MCA are also in demand abroad. The remuneration abroad is very high for MCA graduates and some company's even pay up to Rs. 60 to Rs. 90 Lacs per annum.

It doesn't matter on the course. It matters on your ability, how talented you are, your communication skills, your technical skills.
Both are good.
From my suggestion, go for B.Tech+M.Tech.

You can get placed in a good product based and service based company. You can also get into a firm for job of assistant project manager.