Speed Run or Hard Mode First?

[Beelzebubbs]

Gotta do a few more achievements in ng+ then off to my other two runs. I'm level 200 with most of the best assassin gear, not fully upgraded but almost, all dragon forged. Does it matter?

[Guh~hey~hey~♫]

Speed run can be done anytime. The game doesnt save during speedrun, all the items you'll use wont be removed from your save, the only thing that will change on your save is the achivement and the reward for completing the mode. So having good gear does ofc matter, but what matter most is to stack in your bank all quest items, tons of the best consummables (healing, curing, special arrows, etc...) and a fully upgraded gear for you and your pawn.

For hardmode... only the early game feels hard. Once you figured out the gameplay, it's better to just always play on hardmode because the rewards, especially RC, are bigger making the game feel way easier from mid game.
Things you'll have to pay attention to in hardmode are stamina consumption (so no more spam OP skills randomly while sprinting all the time to get result, you need to become efficient in your use of stamina) and KD mechanics that get way more technical (you cant get cheap knock downs on ennemies with insta-KD skills, you need to actually follow the mechanics).
All in all I think normal mode is the "beginer/tutorial" mode to figure out how the game work, then there's no reason to play anything but hardmode even from level 1.

[toasty frosting]

The only thing I'll say is that playing Speedrun Mode sets your save to Normal Mode, and there's no way to go back to Hard without reseting story progress. So keep that in mind if you start Hard Mode first.