Won't pay for something like this, lots of free alternatives that are 99% of the way there i.e. coworker.com, google maps, liquidspaces, etc

I'd instead suggest you monetize it by getting a shit ton of traffic and only later asking coworking spaces to pay for premium/sponsored listings instead of asking consumers to pay monthly

You should aim to have the most comprehensive directory of workspaces, extensive filtering/searching capabilities, etc. Also write blog posts and do all the usual SEO stuff to try to rank. I suspect you may have trouble ranking given the amount of competition for coworking related keywords but give it a shot anyway and see what happens