B.Tech

In a nutshell, this is a crucial difference. Historically, it was common practice to classify computer engineering as a branch of mathematics. Simply put, it comprises the following:
The integers and other discrete mathematical structures (graph theory, combinatorics, logic)
Linguistic Hypotheses for Computer Code (type theory, compilers, languages)
Information Theorems (crypto, errors, compression)
theorizing through use of computers (complexity, crypto, automatons)
Methods for Analyzing Data Structures and Algorithms (can also include complexity via algo analysis)
AI (machine learning, robotics, pattern recognition, data mining) (machine learning, robotics, pattern recognition, data mining) (robots, AI, pattern recognition, data mining)
Computational Parallelism, Communication Networks, and High-Performance Computing (HPC)
Frameworks and systems (digital logic, OS, networking, systems arch. )
Subjects concerned with computers (often scientific computing and numerics, but sometimes also include graphics/visualization). Graphics (computer vision in some conditions, geometry) (computer vision in certain circumstances, geometry) (geometry, or computer-aided vision)
Software engineering
My view, which is shared by only a few, is that software engineering is a subfield of computer Science. It's vital to remember that in software engineering, everything is built from scratch. This area of engineering is very real and important. You'll encounter typical difficulties associated with the engineering field in general, such as:
The organisation and Design of Computer Programs
Expandability without compromising functionality
Validation, automation, and testing; they are the three terms. Assuring High-Quality Performance
UI/UX
Methods (sometimes) (sometimes)
The second list is meaningless without the information in the first. Learning the fundamentals of computer Science is the first step in entering the more applied field of software engineering. This is the distinction between a physicist and an engineer in any other scientific or technological field. While engineers do make use of Physics the discipline is about much more than just equations and theoretical reasoning.

Yes you can. I have finished an online Post Graduate programme in Full Stack Software Engineering. I ultimately decided to enroll in NIIT after a lot of trial and error. In addition, I discovered a slew of online education options, like Udemy, Coursera, and others. My preference was for NIIT, on the other hand. The technologies taught, helped me transition from a senior IT engineer to a software engineering professional after taking this course. You'll learn the fundamentals of software engineering and how to put them into practise by taking this course. This course will teach you all you need to know about how they operate in terms of design, deployment, services, and much more. The course material is organized to aid you in gaining a full grasp of all of the key ideas. In the world of information technology, having their certification is a distinct advantage.

Yes, you can do Diploma or degree courses in mass communication after a degree in B.Tech. There are the following degree courses that you can do after a B.Tech degree:
1. Master of Arts in Journalism & Mass Communication
2. Master of Journalism and Mass Communication
3. Master of Communication & Journalism
You can do the following Diploma course after your degree in B.Tech:
1. PG Diploma in Journalism and Mass Communication
2. PG Diploma in Mass Communication
You can take these courses at the following colleges:
1. Indian Institute of Mass Communication
2. Apeejay Institute of Mass Communication
3. Manav Rachna International Institute of Research and Studies
4. Indira Gandhi National Open University
5. Jadavpur University.