SHORT ANSWER
Start with Marcus's Gunfire / extra-shot engine route
Journey is the best place to learn the icon language and the pickup loop. Marcus makes the connection between firing frequency and a useful upgrade easy to see.
“Best” here means the clearest fit for the difficulty's risk profile, not a measured universal tier. There is no verified DPS test that proves one Hunter wins every Journey run.
What changes at Journey
The low-pressure introduction. It reduces incoming damage and resource gain, so use it to learn icons and the pickup loop rather than to judge a late-game route.
Create a repeatable shot event.
Vintage Musket, Geminate Shot+, and Reload Speed or Fire Rate.
Check: If the gun is still waiting on long reloads, do not chase crit yet.
Turn uptime into more projectiles.
Quick Fire, Triple Shot, Bullet Attack, then a matching element relic.
Check: The route is working when ordinary fire produces several useful events per magazine.
Convert volume into a stable boss finish.
Critical Chance, Critical Damage, Emperor's Holy Sword, and reload support.
Check: Keep one reliable damage channel; do not add a second engine just because it is rare.
Boss and crowd priorities
Use reload support and crit payoff once the target stays alive long enough for repeated first-shot windows. Keep firing discipline; a burst that spends half the fight reloading is not a boss plan.
Extra shots, fire rate, and a weapon that spreads pressure are the priority. If packs are the failure point, Bullet Attack and volley effects beat a greedy single-target card.
When the recommended core is missing
Keep the physical element, choose Fire Rate and Reload Speed, and use Demonhunter Crossbow or any reliable physical family.
Do not: Do not hold empty slots for one exact skill while the current weapon has no uptime support.