You are seeing conflicting opinions because A) there is no easy or obvious answer, and B) because the average forum user is not an expert or epidemiologist.
Opening schools would have immediately benefits to students' education, physical, and mental health. It would ensure immediate education whereas many have been neglected during lockdown (not all students are financially equal; many cannot afford to study from home, nor have the space to do so. Many also depend on schools for lunches, socialisation, and exercise). It would also be beneficial to the economy (parents will be better suited to attending work during the day).
The obvious risk, however, is that there is no reasonable way of maintaining social distancing and mask use in small buildings housing hundreds of students, many of whom will rebel against distancing and mask use simply because they are rules. This would increase virus spread, increasing the odds of mutations that may alter the antigens targeted by vaccines. It will also put potentially thousands of lives at risk. However, there is equal chance that further lockdowns will pose a danger to human life, as diversity of location; exercise and nutrition; and socialisation are all fundamental to mental and physical health.
I do not know whether lockdowns should continue or stop. But these are a few arguments for each side.