you have a solid advantage over these especially with unathorized build since they're mainly going to try to fight you headon and a right click up close and many left clicks with your sidearm will do the job on the flankers, for example on lex, buck, moji.
against the tanks you'll be a nuisance just shoot their shields off so your team can do some work with cauterizer.
ying is low health, you have to potential to finish her off really quickly if out of position and in your line of sight.
in general you counter most healers due to low health and most having to heal their tank being in line of sight to your scope.
these are pretty much your hard counters, and the reason why the builds are high mobility, to relocate and basically outplay as hard as possible against anything that counters you.
Dredge is a counter due to his high survivability and being able to just smash bombs over ledges being unspottable by you, however in a straight up fight, you'd prolly lose if you don't try to outplay using your mobility to your advantage considering dredge gets a pretty powerful shield when put on low if he's using the right loadout.
I used this build to change position every kill, quickly relocate so I don't get staggered, this build works as a counter to other snipers and to survive when you're being flanked by champs like maeve/evie/moji.
depending on enemy frontline composition and healer composition, for example if you are against inara and terminus with a decent healer such as seris/jenos , get cauterizer tier 3 ASAP.
Wrecker if you're against for example KHAN, fernando, Ruckus, at least 1 of those, then you need to build wrecker for your team.
blast haven/ haven, depending on their composition, double blaster go blast have, double single target go haven.
nimble is very good with Tactical Retreat, as the movement speed will stack insanely, but nimble is only a last choice, for example if you have 300 creds, 1 slot left, everything costs 600 to upgrade or more and it's 3-3, you should choose nimble to add more to your mobility and in turn increase survivability and effectiveness of your repositioning.
CrackShot is a very versatile build, requires a lot of fast thinking and rotation, however, the build for crackshot is pretty simple, and the playstyle of the crackshot build is that of a flank strix style, this build is very effective against snipers and backline damage dealers and to deal with supports, suggestively it works against frontliners as well, but is highly dependant on how your team is doing.
strix takes a lot of time to learn and get very good with, you need to play a lot, but these builds are my recommendations, I do not recommend nocturnal in any way as it only brings survivability but no dmg prescence by any means.
Guerrilla Tactics
Stealth
Generate 30 Energy after getting an Elimination.
Level 2
Infused Crystals
Weapon
Increase the maximum Ammo count of both your weapons by 2.
Level 2
Dexterous
Quick Switch
Reduce the time it takes to Quick Switch to your Pistol by 20%.
Level 2
Grizzled
Armor
Increase your maximum Health by 200.
Level 4
Tactical Retreat
Stealth
Increase your Movement Speed by 50% for 2s after entering Stealth.
Level 5
Level 3
Wrecker
Weapon
Your weapon attacks deal 90% increased Damage to Shields.
Level 3
Haven
Armor
Reduce the Damage you take from Direct and Area of Effect attacks by 18%.
Level 3
Guardian
Armor
Increase the effectiveness of Shields you create by 30%. This does not affect most cards and passives.
Level 3
Unauthorized Use
Flare
Flare deals 250% base damage, has significantly increased Projectile Speed, and has its Cooldown reduced by 10s, but no longer Reveals enemies.
Level 3
Unauthorized Use
Flare
Flare deals 250% base damage, has significantly increased Projectile Speed, and has its Cooldown reduced by 10s, but no longer Reveals enemies.
Level 2
Guerrilla Tactics
Stealth
Generate 30 Energy after getting an Elimination.
Level 2
Infused Crystals
Weapon
Increase the maximum Ammo count of both your weapons by 2.
Level 2
Tactical Retreat
Stealth
Increase your Movement Speed by 50% for 2s after entering Stealth.
Level 5
Grizzled
Armor
Increase your maximum Health by 200.
Level 4
Dexterous
Quick Switch
Reduce the time it takes to Quick Switch to your Pistol by 20%.
Level 2
Wrecker
Weapon
Your weapon attacks deal 90% increased Damage to Shields.
Level 3
Haven
Armor
Reduce the Damage you take from Direct and Area of Effect attacks by 18%.
Level 3
Kill to Heal
Armor
Getting a kill or elimination heals you for 600 Health, unaffected by Anti-Healing.
Level 3
Nimble
Armor
Gain 7% Movement Speed.
Level 1
Infused Crystals
Weapon
Increase the maximum Ammo count of both your weapons by 2.
Level 2
Dexterous
Quick Switch
Reduce the time it takes to Quick Switch to your Pistol by 20%.
Level 2
Bushwhack
Quick Switch
Swapping to your Pistol grants 20% Lifesteal for 3s.
Level 2
Grizzled
Armor
Increase your maximum Health by 200.
Level 4
Tactical Retreat
Stealth
Increase your Movement Speed by 50% for 2s after entering Stealth.
Level 5
Crack Shot
Weapon
Talon Rifle gains non-scoped Accuracy, but deals 900 Damage, its Effective Range reduced to 200, and applies a 50 damage Burn over 1.5s. Stackable 3 times and refreshes on hit.
Level 5
Level 3
Kill to Heal
Armor
Getting a kill or elimination heals you for 600 Health, unaffected by Anti-Healing.
Level 3
Nimble
Armor
Gain 14% Movement Speed.
Level 2
Haven
Armor
Reduce the Damage you take from Direct and Area of Effect attacks by 12%.