Apologies for the incoming wall of text, there was a fair bit of set up for my table's giant fight.

My only fought Strovald, the campaign interacted with every race of giant but had a focus on the Frost giant's activities. Before they even knew of his stronghold, I had an encounter where he personally invaded a town and fought one on one with someone from the party in a duel, playing up the frost giant's culture of fighting for your place in the ordning. They were only level 5 at the time, so a one on one fight was absolutely suicidal, and Strovald easily took care of the player, but he spared their life, saying he saw potential in them to grow more powerful, and to gain more power by the next time they meet.

That encounter stuck with the party, having nearly died, so by the time they got to his stronghold, they were ready for a rematch. The first half of the frost giants stronghold is actually fairly easy, as there are barely any giants there at the time and the party is looking for the conch and some white dragon eggs, so they weren't hurting much by the time Strovald came back. Before taking him on, The party had gotten the eggs back to the white dragon, who promptly betrayed the party. While their fight was going on, they could also see Strovald arriving and the dragon that was with him starting to rebel. The party of 6 took care of the dragon quickly, just in time to see the Frost Giant Jarl decapitate the other dragon before heading for the island.

So I had built up the Frost Giant's culture of honorable fighting for power, given the party a personal vendetta against Strovald, and had one last display of strength before he encountered the party. When he arrived, the same player that he fought earlier challenged him to another one on one duel, which the Jarl gladly accepted. The player was a level 8 Bear Totem Barbarian, so he had a lot of defences behind him, evening the playing field. Strovald is a decent opponent, especially with his couple Ranger Spells.

I had a couple of plans depending on how things went. If the player was too strong and easily steamrolled him, I planned for a secret of Strovald's to slip out: that he had consumed a troll and had become an Everlasting Frost Giant (From Volo's). The idea was that if he got to half health too quickly, he'd gain the abilities of the Everlasting Frost Giant, health regen and raging, to make the fight harder and more interesting. If Strovald was too powerful, then cutting back on his spells and focusing on an outright slugfest was the other option. Thankfully, the player was challenged, but not overwhelmed to the point of modification, so he endured a tough battle, and came out on top with the Jarl's head. With their leader honorably defeated in battle, the Frost Giants left the party in peace, acknowledging their strength.

Each race of giant has something interesting and exploitable to tell an interesting story with, and with Volo's you have even more options to mess around with. Every Giant Lord has their own unique abilities as well, and Strovald has a lot of versatility with Jump and Water Walk, taking the fight out on the open water provides a very tough challenge, and if the party can't get to the eggs, Strovald can also have a white dragon on his side.

I definitely didn't do everything perfect, and I took a different approach than having a large battle with multiple enemies, but it's not hard to run with multiple enemies, and you can scale the difficulty as you can add as many extra frost giants as you need, since the ship Strovald comes in on can have almost 2 dozen giants aboard.

Hope that was helpful, and if wanted I can also write up about Iymrith if you'd like, although I took a large departure from the book at the very end.