This is a great addition to a Dragon Heist campaign. One of the flaws of Dragon Heist is that it's a module named Dragon Heist in which the players do no heisting. As a result, one of the easiest ways to fix this is to make the 3 "keys" to the Vault of Dragons part of the villain lairs, such as Xanathar's.

It's extremely easy to sub out the dumb aboleth magic item for something else (especially because the Stone of Galorr in Dragon Heist IS ALREADY AN ABOLETH IN A MAGIC ITEM) that the players need.

The best and most usable part of the module is the fish tank map and entire 3rd encounter. There is some tunnel stuff in the early part that you can scrap and the setup is paper thin, but luckily you don't need any of that crap--you already have the players in the lair, they just need to get into the fish tank, and that's what you want the adventure for anyway.

It's $3 on DTRPG and has a pretty good statblock for fighting a giant goldfish. Any DM worth their salt can use this in an ongoing context. Wouldn't run it as-is for a one shot as it's completely devoid of good context.

After playing the adventure, and feeling somewhat disappointed in it, I read through the module to see if I was missing anything. And basically, it's a simple low level and very repetitive dungeon crawl underwater, with no real chance to role play. Could be fun for a first time player just to get a handle on the mechanics of battle, but it offers little else.

(SPOILERS NOW) It's frustrating also that you can't defeat the boss in battle unless the DM goes against the module and lets you, so to survive you have to make a deal with an Aboleth that you can't fight that will likely be against every instinct of the PCs.