It's probably by amount of shrines/spirit orbs. Weapons also get stronger as you progress (they usually have a secondary effect, to compensate for weak weapons you get on late game).

I really like the Great Plateau. The whole 'island' really is tutorial island without being obvious and allowing you to explore on your own. I got killed a few times but was able to get more used to the controls and learn methods and strategies. Definitely made me more prepared for when things get harder :p

Funny, after reading this, it feels very much like a video I watched from Arlo. He made similar points about the weapon system and how it teaches you various things about the combat, such as using different weapons, being more creative and just becoming better at fighting. Really well made points which makes a lot of sense as to why the weapon system is how it is.

Dispatching Lynels with ancient arrows defeat the purpose of fighting them in the first place. Since the arrow just makes them disappear and no loot is left behind. That may be good as a last resort if you're afraid to lose the fight, but if you want the loot you still have to fight them the old fashioned way. If you're not good (if you're not using flurry and perfect guard for example), you will use all your ressources before the fight is over. You get overpowered against Lynels only once you know how they behave, learned how to react to their attacks, and once you manage to trigger said flurry and perfect guard at will.

Otherwise, they will still be the toughest enemies in the game.

Wow, that explains what happened to one when I accidently shot my ancient arrow at one. I was so confused when it just disappeared.

Wait until you fight against Silver Lynels... They're the ones I hunt now, because their loot is ludicrous.

Two things. First, you can just as easily use Urbosa's Fury and dispatch them with minimal effort, since each hit does about 25% of their health and stuns them as well. Combine that with a 60 damage weapon or so and they'll be down in 40 or so seconds. Assuming the player has Mipha's Grace and Daruk's Protection, they're entitled to three free hits and an entire respawn + additional hearts before they even have to begin burning health restoration items.

Secondly, the fact that you don't get loot doesn't negate the fact that the player is still incredibly OP. Sure, there are consequences to using the "instantly kill the most powerful non boss enemy in the game" option, but that's just it. The very fact that the player has access to a weapon that bails them out of nearly any bad situation they might get themself into demonstrates just how incredibly powerful Link gets.