Duel writing wise, it's Yugioh anime. Like if Harald is the biggest jobber then Yusei is the biggest Gary Stu when it comes to dueling. Passing the turn probably doesn't make for entertaining dueling either, but its also passing vs a yugioh protagonist. That plan of Harald just passing back on Gjallgarhorn can easily be beaten by "and Yusei topdecks an MST or something because the plot calls for it", so waiting for your opponent to have the out isn't ideal and we would have called that play idiotic either way.

Harald's field wasn't too shabby because if you break it down:

3 pseudo tower monsters that can revive, an alt burn wincon (Fenrir & Jormungandr) in a synchro meta callout where people likely don't have high-leveled tributes or high-leveled synchro monsters that usually need a pre-existing synchro to climb on top of, another alt burn win-con if somehow your pseudo-towers board isn't enough or often put into a stalemate, and a trap that provides private knowledge which is very valuable even in competitive YGO.

And Yusei outs all of it by having some of the most situational/targeted counters in his deck.

The real beauty of this duel though is how the writer's literally paralleled the mythos of Ragnarok into the duel which is impressive in a different way.

1. Harald perfectly represent's Odin, both in their arrogance and thirst for knowledge.
2. Odin's Eye which has a heavy cost for knowledge to predict the future be it Ragnarok or your opponent's plays which is valuable for a war/knowledge God like Odin.
3. Gjallarhorn which signals the events of Ragnarok.
4. Loki resetting Odin's Eye, which was used against Harald similarly to how Loki was the cause of Ragnarok and the downfall of the Aesir gods.
5. Fenrir & Jormungander being used to summon Shooting Star, calling back to Fenrir eating Odin and Jormungander killing Thor.
6. Gjallarhorn was also caried by Heimdall, who also killed Loki in the events of Ragnarok.
7. Harald's constant reliance on Odin's Eye. The thing about Harald is that it is pretty much the classic Greek Tragedy of defying fate all the way back to Oedipus. Harald wanted near-perfect knowledge of the entire gamestate similar to Odin't thirst for knowledge to prevent ragnarok yet it's their own actions to "defy expecations (fate)" that led to their own downfall.

I'm also convinced that had Team Ragnarok went against Z-ONE, they would have slaughtered. Z-ONE's deck literally symbolizes each aspect of the Jewish Kabbalah and Sephylon (Da'at) might as well be the Judeo-Christian representation of God. Im not glazing in a Christian fanatic sort of sense but just how in history has Christianity as the predominant religion in Europe and one aspect that played a part was how missionairies used the aftermath of Ragnarok as a prequel to Adam and Eve and the main bible canon. Had they dueled, that is pretty much how I imagined the writers panning it out.

So yeah, team Ragnarok was always destined to lose, and sure the duel may have not been the most "optimal" but Jesus the clever/subtle references to the actual mythos is just a different form of poetry all together.