If you're looking for software with strong rental accounting capabilities though, there are apps that have this functionality built into them (rather than paying extra through RentRedi to use the REI Hub.

If you still like the deal with those conservative numbers, then any extra function from the converted room is just a bonus for tenants or end buyers.

What is in it for you is not just the bump in monthly rent but also a boost in overall property value, since a larger, more functional lower unit makes the home more versatile to buyers down the road.

Use tools like:Airbnb Analytics: Monitor impressions, clicks, and overall CTR.IntelliHost: Analyze your listing for category placement and CTR improvements.RankBreeze: Track your listing's performance and ranking changes.You can also A/B test your photos by rotating lead images or running Meta Ads (Facebook/Instagram) or Google Ads to measure which photo drives the most engagement.The Airbnb algorithm is continuously evolving and every host should pay attention as new features are rolled out. 

Decks usually aren’t my favorite because of their maintenance costs, but in this case it created great outdoor living space that made the home much more enjoyable and functional.

Exploring other options like Appfolio or Apartments.com which might offer the balance of support and functionality you need, is a sensible approach.

Quote from @Geeta Bihari: Cash flow will be a function of how much money you put down/amount of leverage you use. 

What are the functional issues? 

Make sure any lender requirements—cash management, carve-outs, reserve controls—still let you function as co-owners.

The BiggerPockets community is filled with people who can share valuable insights and past experiences.I'd also recommend using the search function to find people and topics of interest here on BP.All the best to you!