New and veteran players alike may wonder how to clear the numerous Challenge Quests that arrive with the titular event. The least expensive setups are solos, and present a clear baseline for all other clears.
Conversely, they offer a somewhat painless way to approach these quests for players with undeveloped rosters. With that in mind, and with the help of friend supports and some of the showcased videos, I'm sure any player could tackle these challenges face-on.

For an in-depth explanation of the various gimmicks employed in these CQs, please refer to Battle in New York 2020's Fandom Wikia page.
Please note that this sheet doesn't offer farming comps. For those, we recommend checking SaberOfAvalon & xzero's sheet for farming comps instead.
You can also check #resources on the Atlas Academy's Discord server for more links.

Rice Balls Chain-Store #01・Tawara Touta

Flame Gate・Leonidas

Flame Gate is somewhat challenging to solo due to Saber Shiki and Nero being the only two servants capable of doing it. However, it remains relatively easy to do with any AoE Saber and appropriate supports.

Phantom of the Skyscraper・Okada Izo

Even Marie can solo this, which is very telling of the quest's difficulty.

Come Now! To The Land of Jaguars!・Jaguar Man&co.

When it was released this CQ's difficulty was blown out of proportions. In truth, it is perfectly doable with simple comps.

Dollar-Cent Leasing Shop・Queen of Sheba

This challenge quests features gimmicks that might cause solos to be a bit troublesome. The encounter isn't overwhelmingly hard and can still be carried by a friend support and a bunch of fodder units:

Sweets Universe・Mysterious Heroine X (Alter)

Unlike the vast majority of CQs, there are no known solo runs of MHXA. The simplest way to do it is through stalling. These are some example runs that might offer ideas on how to deal with MHXA and her army:

Golden Metropolis Finale