I've been tinkering with different ways to make questing more fun without destroying the RPG aspect by going completely naked and punching things. I found a nice compromise that works for me and I've been testing it out throughout the Elsweyr storyline, tweaking it further, and I'm quite satisfied with the results - there have actually been some quest bosses that I actually died a couple times at, that I didn't have to hold back on, and in some cases I had to actually step up and make sure to dodge to survive with the rules I was using. Haven't felt that with questing since before One Tamriel, on new characters or max level characters.

It wasn't perfect, some bosses still didn't pose much a threat and most trash enemies aren't dangerous but that's okay for the most part. The AFK survival time was reduced massively and some mobs are actually a little tougher than others and still can prove a little dangerous when there's multiple - questing enemies generally seem to be a bit weaker than standard overland enemies minus some exceptions I've noticed. I tried to balance it around enemies like Haj Motas in overland - so I could make it so those were difficult enough to pose a threat to dying to if I don't pay enough attention, but without making them take so long that it becomes tedious - and while still retaining some RPG element like "there are better items I'm allowed to use" instead of "I'm not allowed to use anything".

So with that all said, here's a (recently!) Flawless Conquerer's guide on how to die to quest bosses:

-No Champion Points
-Bank everything you currently own while HM questing
-No Crafting Made/Altered/Improved Items (no food/potions/armor/weapons/enchants/etc made via crafting or improved/atlered via crafting)
-No items from trading with other players or through guild stores
-No Crown Store/Daily Reward/Level Up reward consumables

I started out with just generic cp 150 gear from merchants but I'm still able to earn better gear for HM Questing by doing overland content, getting them as drops or rewards. It'll be harder to complete sets and getting the ones I want but having that available satisfies my RPG need to not feel like I'm just nerfing myself into the ground the way that going naked or using level 1 gear felt.

This also means that the only food you can use are the ones you can get from merchants or found in overland sitting around, which are always 1 stat foods at cp 150 (if you're level 50 cp 160+). You can still choose if you want it to be a health food or your primary damage stat, and actually, it was good for me to have both - some quest bosses hit hard enough that changing to health food helped me survive.

Also the only potions you can use are merchant bought too, but you'll mostly only want to use the health potions because of the next part...

-No Self-Healing/Shield Abilities
-No Pet abilities that can draw enemy aggro away from you
-No Ground Target AoE DoT abilities specifically (like caltrops/endless hail/liquid lightning/blockade of fire, etc)

These abilties, no matter how weak you are, are too OP for overland balanced combat. Self-healing is just simply too strong for overland, so if you want any sense of danger you have to remove it. It makes you think differently about boss fights, and you need to start to dodge too to survive, which is nice. Pet abilites tanking also is too easy, for me at least, and the ground-target AoE DOT abilities do too much damage compared to other skills that turns what would be an interesting boss fight into a dangerless scenario, again at least for me. You can still use AoE abilities, and you can still use DoT abilities, and you can still use ground target abilities, or even AoE DoT abilties, but not ones that fall under all 3 at the same time. That was the final tweak I added that made my questing experience enjoyable, and even made me start thinking about other abilities to replace them with - using AoE root abilities so I can survive the several melee enemies coming at me during a quest because I might otherwise actually die because my only means of healing is a long-cooldown duration health potion? Never would have thought I'd use that when questing.

I won't spoil which ones, but a couple of the Elsweyr main quest boss fights actually could kill me if any two of their attacks hit me in a row, I could survive one hit and let my health slowly regenerate and take another, but if I took 2 in a row within a several second period, I'd be dead. It felt great! The big antagonists actually felt like the threat they were built up to be instead of pushovers this way.

Anyway, I just wanted to share my HM questing rules in case others wanted to give it a try and see how they like it, I know a lot of us who like and like lore/storytelling are in a tough spot because ESO only offers 1 or the other, not both at the same time. I'm still holding out hope for an optional toggleable hardmode or debuff or something to give this same feeling without needing to refrain from using any abilities or gear, but in the meantime this is the closest I could get without compromising too much for me. For others I'm sure more tweaks will have to be made, but this could work as a good starting point for some. And if you don't need any of this and enjoy questing without any restrictions or added difficulty, then great, I'm glad you're enjoying it!

Also if you have your own personal HM questing rules that you're satisfied with, feel free to share those in the comments too.