Hello Aspirant

I don't think PCB would be tough. Rather , you may find PCMB tough because of one additional main subject.

The only problem with PCMB is that all these are main subjects because of which you need to pay attention in all the subjects equally.

For an average student PCMB is a bit difficult but if you have the zeal that you can do it and you desire spending your time while doing maths than go for it.

Thank you!