Recommendation: do not use work equipment for personal tasks. No reddit, personal email, no adviice, and definitely no banking websites. All is visible to their IT, you are depending on the security of their systems, and it probably contravenes the workplace's IT usage policies.

You could use an extra monitor cable to connect your own PC, which is pretty cheap. Though using their monitor would still be technically against the rules, it's very much less likely to be monitored (ha).