Halo Wars 2 Act 2 missions are garbage?

Is it just me or are the missions From The Deep, Hold The Line, and From The Dark laughably bad in terms of design?
After playing From The Deep, I thought that this had to be the most annoying level in the game because of how much -Yoink- they throw at you and how little time you have to prepare unless you already know what to expect, and you better make sure that you get on those locusts the moment they spawn in or else your structures are going bye-bye.
Unfortunately, Hold The Line proved me wrong by being even more annoying than the previous mission. You better make sure that you build on every single turret spot and you better make sure that you already know which types of enemy troops come from which routes (which you can only find out by losing or looking them up), or else you’re screwed. Also, how tf are you not supposed to automatically get rekt by that swarm of vehicles that come in at the 20 min mark. They throw like 50 vehicles at you that will break through your barricades in seconds and wreck the particle cannon, and there’s no way that you can know how much troops they’re throwing at you until it’s too late. Only managed to beat this level (and rather easily btw) by spamming nothing but air vehicles (awesome gameplay).
And now Under The Dark is shaping up to be even more annoying than the other two missions! On the first part, they give you nothing but a small -Yoink- two building base, so it takes forever to build up resources and destroy the enemy base. Also, on my first attempt, the kodiaks were getting destroyed by enemy troops, but I thought it wouldn’t matter because my troops were about to destroy the enemy base (which is why we are given the kodiaks in the first place), but apparently you lose the mission if all the kodiaks get destroyed, even if you can destroy the enemy base without them. Makes no sense. Then there’s the 2nd part, which makes the first part look like a masterclass in game design. Once again, you get a tiny two building base, with another one located further up the map, and a few power nodes scattered throughout the map. Problem is that you have to buy kodiaks, which are hella expensive when you have barely any plots, and the enemy gets to use their leader abilities every 10 seconds, so when you build up an army, they instantly get rekt and you have to start over again. I couldn’t even get past the 2nd shield generator before rage quitting.
Also, why do our troops have to move slow as molasses in this game? In HW1, you could get the adrenaline upgrade, but 343 didn’t bring that back for whatever reason. I get that since I’m playing on Heroic, I should expect somewhat of a challenge, but a ton of these missions as of late seem to be just very poorly designed. Can someone please tell me that the next 3 missions are more bearable?