My trusty starter since ritual: Deadeye fireball miner - Explanation and showcase

Showcase: https://www.youtube.com/watch?v=powNyRbqNYc

PoB: https://pobb.in/k9rcdDU4toq7

This has been my to-go league starter ever since ritual.

What it does: Clear maps like crazy. Ignores any mapmods. Perfect early alch'n'go build. Outside Headhunter/KB/proliferation stuff, i've hardly seen better clearing speeds ever, and whenever i try i new build this is always something i struggle with. ("Why does this feel so slow")

What it doesn't: clear ubers. Sorry, i can't make it do ubers, either a skill issue, or just WAY to little defence. When killing stuff before it kills you is valid, this build works VERY well. When that doesn't work, the build fails. Simulacrum 20+, ubers, that stuff, is just near impossible to do. Feared is pretty hard too, and requires a bit of luck. Any Maven-arena is a tough fight: there is no walls which really boost the damage.

Clear speed vs investment needed: NON-EXISTENT. Most expensive piece is the staff, the rest is just 'whatever you can tack on'. Usually i grab a 10c Leadership's price and just call it a day. Get the leaderships price, a decent staff, and dying sun, and you're pretty much set. Of course, the inspired learnings are pretty damn good, obviously, but they don't make the build function :)

Leveling: if you can afford it on league start: get a 4-link tremor rod on lvl 41. If you can get it, it will wreck the campaign and white maps for you. It'll slow down around yellow/red maps. You'll need a +x to level staff gem and spam with 'essence of woe' to get the wanted staff. Most important upgrade for damage is the leaderships price. Make sure to invest a bit in "effect of non-damaging ailments", you can use divergent fireball for that. Dying sun is a damage multiplier, and should not be underestimated.

Single target damage explanation: Using the interaction of tornado, a +1 chain fireball and snipers mark, you get LOT of chains/explosions for the fireballs. Fireballs that hit the tornado and have 1 chain left, will chain back to the enemy. Fireballs that have no chains left and hit the tornado, will explode, AND HIT THE ENEMY. Use a totem linked with tornado to keep it summon tornados which can be hit. Fun fact: the 'reflected' damage from the tornado is not blocked in hall of grandmasters and can be used to kill those pesky recover on block builds.

Other notes: I haven't played this league heavily, so haven't really optimized this character.