If there are some melee champs you really want to play, then play them. You need to learn how to play a losing match up and the fear of facing Darius is preventing you from exploring new champs.
That said, Darius is far from the only challenging opponent you'll face top. There are at least a dozen champs that are designed to simply pile drive the lane and usually without regard to what you pick.
My biggest piece of advice is to just learn how to deal with losing your lane. Before his rework Garen ate shit most games and always came back for seconds, from this experience I learned a few key things about coping with and flourishing in match ups you typically lose.
- Accept that you will lose creeps. You will lose creeps. Accept it. Remain in exp range and just give them up, entice the enemy to push by standing near your minions so that they use aoe spells. Learn how to cs under tower, manage your spells and autos so that you get the majority of last hits. These two things are imperative - concede cs when it's too risky and learn to cs at your tower while under pressure.
- Learn what items you need to build in order to survive. If you're a bruiser pick up 2 ruby crystals on your first back. Defense will only serve you, it will not hinder you. All those "tank" components eventually build into juggernaut items so you are merely taking a necessary detour. Matching items with Darius (or any lane bully) doesn't work because they are designed to win early and their stats reflect this, they always have more and often have a steroid on top. Know which specific defense items you need to overcome early weakness and then worry about building damage.
- Learn your own base damages until they are second nature. Since you will be building moderate defense you will be relying heavily on your bases until about level 9. For most bruisers, and especially tanks, you can safely trade on just base damage - tanks are actually designed with high base damage because they aren't building ad/ap. Your defense items will either provide you with burst mitigation (hp) or sustained damage mitigation (resists) and you may end up having the advantage through tankiness. This is when you'll need to know how much damage you do naturally, in order to secure kills.
- Search for specific strategies you can use to gain an advantage. Prerework Garen I would take Phase Rush into Darius to have small trades that I controlled. Another example is taking Predator into ranged or immobile match ups that are too dangerous to normally approach. If the champs you like have keystone options, explore them all until you find something that works.
- Above all else do not buckle under the pressure and tilt. Stay calm, concede cs, prioritize defense components over offense, call for ganks, roam If you can, and just get through the lane phase.
Good luck dude, top lane is a harsh place these days but will always be my favorite lane. Don't let the enemy affect your mood - just chill out and take whatever they let you. Whether that be 1 minion or their life, let them make the mistakes and punish them for it.
