melodie

Character
Melodie is a close range assassin and a little bit hard brawler to understand. Many people probably go straight into showdown without checking her with bots first and only then ask "where's the damage?" this is honestly sad.
So, melodie has a completely unique mechanic. Each attack, if lands, creates a note orbiting around her for a short period of time. Each time note passes through an enemy it deals a lot of damage. So, basically, you don't kill with your attacks, you kill with just being close to someone.
With that in mind, we proceed to the gameplay and gadgets.
Gameplay
In order to properly win in any modes you need to learn how to manage your notes. First of all, you should always try to maintain the maximum amount of 3 orbiting around you. Without the passive they can go off very unexpected and not at the right time. Which leaves you, obviously, unsafe.
Notes disappear in around 6-7 seconds after you get them. Try to land your primary so you don't lose notes.
Killing with melodie is rather simple with ult and pretty hard without. Ult gives you free 3 dashes that let you go in and get out at the same time. Pretty strong for fighting against multiple people. Melodie is kinda bad against many long ranged brawlers since she can't do much against their poke/harass/control. Long ranged primary deals almost no damage, so you should rely on your ult.
Against melee melodie thrives. Thing is, your notes keep them on perfect distance away from you. At maximum range of your notes they can't oneshot you, but you deal insane damage to them. You can just kite them to death.
Play around bushes with bulls and others, check bushes and get notes with your primary on then, use ult to engage and get out from ranged brawlers and always try to fight early on showdown.
Gadgets
Wider pitch is just perfect. You get greater zoning potential against melee and great chasing potential against ranged that can easily get away. Also you can hit through walls with it.
Interlude is not that bad comparing to wider pitch. If you feel that you are gonna get oneshoted on certain maps, use it.
Passives
my way to go is Fast Beat. Along with wider pitch and her ult Melodie is a serious threat to everyone. You can both kite melees and chase down ranges. Wider Pitch + Fast beat and melodie just becomes a different brawler to be honest.
Extended mix is just useless. Primary is not that hard to hit and definitely has not that big of a cooldown.
Some things about different brawlers
Frank is a hard one. He has enough range and hp to outlive you. There's not much you can do, but you can try to run him down to low hp with primary and end with your engage.
Mortis just dies when he dashes in you. Honestly you just can't lose to Mortis on this brawler unless he killed 8 other people in sd already.
Buzz is hard. You can kite him with Wider Pitch, but if he hits the torpedo, you are most likely doomed.
Edgar is same as Frank, but he heals himself. Disengage with ult any time he jumps in and you should be fine. There's still 2 dashes left anyway, so just run him down with primary.
Piper is easy. If she uses the slow gadget you still can just walk around hitting her with notes, if she just uses her ult you dash after her and catch on spot.
Mico. Yeah you don't win that. You just don't. Nuh-uh. His entire kit counters yours. Your scariest fear.