It's hard to hear with the first baby, but YAGNI ("You aren't going to need it") applies.
Unless your baby was born with political enemies, (it's fine to) get a simple rechargeable audio monitor.
Source: for my first kid I setup a secure wireless camera with night vision. For my latest kid I got a cheapo glorified walkie talkie. They're both fine (the kids are both fine, and the solutions are both fine.)