Like it or hate it, one of the hallmarks of Waterdeep: Dragonheist is the fact that the book gives you a lot of suggested actions with minimal details. Sometimes, this can be a wonderful way to tighten the narrative or let your characters develop their bond, but sometimes it's a huge pain. Enter Waterdeep: Expanded Faction Missions.
This beefy, 43-page supplement expands each of the faction missions from their three sentence summary into a one or two page adventure. You get an adventure background, suggested tips for how to run the adventure, more information about the key players, and expanded treasure, renown, and experience information.
Additionally, you can use these mini adventures as side quests for players to go on to earn money, join factions, and learn more about Waterdeep. Although they do intersect with WD:DH, they're easily tweakable to be their own standalone adventure, which is quite helpful if you need something short and sweet to entertain your players.
The only thing I would prefer is if there were maps for some of the missions. Not all of them require a map, but some do, either because of the location or terrain, so those would be a nice, added bonus. But it truly is a minor thing, and, hey, you have so much other information that you can't really blame the creator for not doing even more.
If you'd like to implement the faction missions but don't want to have to spend a ton of time thinking of the particulars yourself, I do recommend Waterdeep: Expanded Faction Missions. It's pay what you want, and the suggested $4.99 price tag isn't unreasonable for what you get. It's also well edited and easy to understand. Definitely worth the purchase!