In something like Storm King's Thunder, you use about 25% of the book because you don't go after all of the giant tribes. Cut down random encounters on top of that and you're left with a pretty short experience.
My suggestion
High Level Campaign, which is always a nice challenge for a DM: 9th level+
Overlap SKT events (not the entire adventure) with RoT as the main story plot, perhaps have the option of
Frozen Castle by Kobold press. Have the PCs clear out one of the Giant Lairs/Dens to get +1 reaction on the RoT Scorecard and use SKT chapter 3 for when the PCs travel in the North.
While the PCs are in Waterdeep for one of the Council Meetings - run
The Lich Queen's Begotten
NOTE: Remember Githyanki and Tiamat are allies so it makes sense to have a force of Githyanki attempting to stop the PCs from disrupting the ritual to bring Tiamat in the world. The adventure was designed by M.T. Black and overseen by James Introcaso and Shawn Merwin. These guys are reliable and good-content contributors.
Suggestion to tie in one of the areas of DotMM to the main storyline (Illithids / Githyanki)
Then finalise RoT - with the backstory that other PCs (your past campaigns) succeeded in rescuing Hekaton, so you have giants as allies in the fight.
Lastly close the campaign with a 5e converted version of Chris Perkin's Dungeon Magazine adventure,
The Lich Queen's Beloved. It ties perfectly with the earlier tLQ-Begotten.
Starters - A smattering of giants, devils, wizards of Thay and some illithid
Main - Plenty of dragons, githyanki, an evil cult and dirty politics with the you-know-who of the Sword Coast
Dessert - The pièce de résistance: Tiamat & Vlaakith CLVII