Beginner
What is the Power Level like? Why would I pick Android 16 over Ultra Instinct Goku?
Every character in DBFZ is roughly of the same strength (this is explained in the Story Mode!). Instead of big numbers = good, the characters are shell for different playstyles and movesets. You can pick Android 16 if you enjoys dunking Gokus, or you can pick Ultra Instinct Goku if you enjoy shutting your brain off.
There are Tier Lists comparing the characters' strength in competitive play, but understand that any character can still beat any other character. What matters is the strength of the player.
I heard that autocombo and Super Dash ruin this game. Is that true?
No.
A matter of fact is that DBFZ is designed around autocombos and Super Dash. If you cannot stomach these mechanics, then the game likely isn't for you. Autocombos and Super Dash do have quirks that make them goldmines for funny clips, but just keep in mind that removing or "nerfing" them will not make it a better game.
Is this game a party game?
No.
...but actually...
It is a party game in the sense that it's unashamed of giving players complete freedom in doing whatever they feel like, whenever they feel like doing it. The game can be very chaotic at times, and can seem to reward players for simply pushing buttons rather than being precise.
It's not a party game in that it's not competitive or takes no skill to win. As with the nature of all fighting games, a player of higher skill level will consistently win against a lower skilled player. If you lost against a "masher", try to review the matches and figure out what went wrong. Maybe they weren't making random decisions as you had assumed, and if they were, maybe your skill level wasn't much higher than theirs.
Terminologies
What is a lariat?
Lariats are fast, forward-advancing special moves that cover a lengthy distance. The nickname started with players comparing these moves' functionalities to 
Bardock's Rebellion Spear
GuardAllStartup7Recovery20Advantage-4, one of the first move in DBFZ to have these attributes. The animation of Rebellion Spear is similar to a professional wrestling strike named "Lariat", which an attacking wrestler runs towards their opponent and wraps an arm around the opponent's upper chest or neck, forcing them to the ground.
What is a ToD?
ToD stands for Touch of Death. A ToD is a combo that does 10,000 damage or more, K.O'ing the opponent from full health.
What is a Medium starter?
Medium starters, or M starters, unscaled starters, ToD starters are attacks with proration value of 100%+1 (or higher). If an attacker lands a hit with one of these moves, their following combo will do very high damage and can potentially be a ToD. The term comes from that fact that most Medium/M normals have this proration value.
What is a forbidden ___?
A forbidden starter is often referred to the second hit of L autocombo (5LL), which is a Medium starter. It's "forbidden" because it's an uncommon combo starter that can potentially K.O. the opponent, so they were unlucky or unfortunate to get hit by it.
A forbidden oki is an okizeme that's strong, but utilizes weird applications of attacks and thus uncommonly seen.
What is a raw tag?
Raw tag is a Z Change (tag) done outside of combos (raw).
What is a DHC?
DHC is an Ultimate Z Change, where the Point Character leaves the screen and have an Assist Character jump into the screen and perform a Super or Meteor Attack. The term comes from a similar mechanic called Delayed Hyper Combo found in the Marvel vs. Capcom series.
Infil Glossary Entry: https://glossary.infil.net/?t=Delayed%20Hyper%20Combo
What is a fuzzy?
See here.
What is a Happy Birthday?
A Happy Birthday refers to hitting two characters at the same time. This usually happens because someone tried to call their Z Assist but got hit immediately, and the assist gets caught up in the mayhem and has to go along for the ride too.
Infil Glossary Entry: https://glossary.infil.net/?t=Happy%20Birthday
A move that "can't Happy Birthday" will drop the assist out of the combo to prevent potential team-wipe combos.