Destiny 2: Lightfall - Where To Find The Thrilladome Lost Sector

gamespot.com:

Trouble is brewing in Destiny 2: Lightfall's Neomuna arcade, as the Vex have discovered a backdoor into the Neptunian city's systems through one of its entertainment areas. Fortunately, the city has you to count on for its Vex problem in this lost sector, which combines a futuristic gaming location with Vex simulations to create a unique area to explore. The Thrilladome lost sector, which has a 1780 power level recommendation, can be challenging, but it's one that you'll want to prepare for after the Lightfall campaign ends.

For the Unfinished Business Exotic mission that will ultimately reward you with the new Deterministic Chaos machine gun, you'll need to dive into this lost sector as one of the quest steps. Once you're done with that mission, the Thrilladome is an excellent location for farming Vex as part of any possible seasonal objectives or bounties, and it has some great sections in which to practice your new Strand-swinging powers while you're dealing with the pressure of having time-traveling robots shoot a barrage of lasers at you.

For more Lightfall guides, you can check out where to find the Hydroponics Delta lost sector and where to find the Gilded Precept lost sector.

Head to Liming Harbor and make your way to the building at the end of this location. You'll see a lost sector marking on the wall to guide you towards the Thrilladome.

Go inside this building, and jump up to the second floor.

On the yellow wall, look for this hatch.

Go through it and follow the path, until you reach a vent that you can break open.

You're now inside of the Thrilladome, which is crawling with Vex. These are mostly cannon fodder Goblins and Hobgoblins, with a few Minotaurs thrown in to mix things up, so pack some Void-energy