The Zelda franchise isn't about extreme difficulty. It's about exploration and puzzle solving primarily.
If you want extreme difficulty vis-a-vis enemies, you should look into other games. Zelda was never meant to be super-hard, nor should it be.
The NES installments were only "hard" in the same sense and for the same reasons that most NES games were hard - due to the limitations of the system. Lack of ability to save progress, less precise controls, etc.
???
You know the Original Zelda's had saves right? Like, complete progress saves.
Was nothing limiting about it. Nor limiting about the controls. Once you mastered the controls, the real hard things about the game was exactly What you described. Exploration and puzzle/ Dungeon +Palace solving.
The original Zelda was legendary for its exploration element. I literally had a hand drawn map showing where you needed to bomb every wall, burn every bush, push every block, blow the flute, etc to find passages.
AOL gets a bad rap for difficulty, but it really wasn't as hard as the first game, Great Palace aside. Some of the palaces were still mazes you had to solve, but the gameplay itself was easy unless you had no patience. It took me a quarter of the time to beat AOL as a 12 year old than it did TLOZ.
Let's not confuse either of these games for NINTENDO HARD type games like Battletoads/Ninja Gaiden/Castlevania 3. The gameplay itself was simple 2 button pattern recognition vs enemies. It was the searching and exploring that was hard. Making sure you had armor and Sword upgrades before tackling Wizzrobes, etc. You really had to dig in those original games to in stuff, whereas games of today spoon feed the answers.
When I see 20+ year olds fumbling with the 2 button controls today complaining about difficulty of old games, ill admit, I laugh my head off.