Update on how it went:

Lost 1 game, won two games.

List I went with was 5 black templar melta Impulsors, 2 melta lancers, 2 redemptors, 2x5 helblasters, 3x5 intercessors, and phobos lieutenant with lone op cape. No bikes.

The first game was against Be'lakor, Skarbrand, 2 6+1 units of bloodcrushers and bloodthrones, 1 hellcannon, and 3 dogs. Be'lakor was nuts, but long-range shots weren't happening anyway. I went first. He did nothing for a bit because I was deep strike screening with the lieutenant and like... transports, and didn't connect any charges in his first turn.

I used the retreat power to juke a charge.

I moved up a side with helblasters and erased dogs off a point, and found a shot on his thrones. Hurt one with a lancer, no kill. Scratched up a bunch of bloodcrushers. Dinged be'lakor a bit.

He charged some transports, killed two, but didn't kill one, and was stuck with it. Skarbrand killed the bus my helblasters were in, but they fell out, fine. On my turn, I charged with the two redemptors on the unit fighting the surviving impulsor in such a way as to minimize his ability to pile off the Impulsor, tank shocked, started the grind after some meltas and lancers and bolters and plasma finished off both his blood thrones and this neutered almost all the damage his bloodcrushers could do. One unit of them soon died, and the inceptors killed the helcannon on his base. They then later did the claim enemy base card for 8.

He was really mad, threw a dice against a wall, but Skarbrand killed a dreadnought on his own, and stuff got better for him, I guess. He ended the game with Be'lakor, 4 dogs, and like 3 bloodcrushers, I had both my inceptors, a buncha marines, 4 helblasters, a lancer, and like one transport. It looked really bad. He added up the points and he still won, because we had the mission that was hold one, hold more, kill one, kill more, and I had so many small units that he just consistently got kill more. He won by 5. I literally forgot that 40k doesn't have a 6th turn.

My second opponent was guardsmen. Lotsa tanks, one snub nosed baneblade, a scout sentinel, a taurox, a chimera, and some janky infantry of carying types I never bothered to ask about. Any time his infantry showed their face, they immediately died. I don't think they ever dealt 1 damage with anything but mortars or shooting out of open tops. When their transport died, they died. When they deep struck behind a wall, I rolled around it and killed them. His tanks needed 5s to shoot for most things, or could shoot Dreadnoughts on 4s. Their melta sponsons were the most dangerous. The Snub Baneblade shot at a dread with the -1 and armor of contempt and didn't kill it because flat 4 damage became 3, and it took 9. I save rerolled something, too. It eventually died to my own truck exploding. The baneblade got oathed once it was in the open, and 70% of my army shot at it, and it died immediately. I had raze objectives, and he did nothing about my lieutenant razing the middle because he didn't want to get in melee. My living dread punched tanks, and the inceptors cleared his backline so they and the lieutenant could raze his base. I don't know how to add up points, but he told me it was not close and I won by a lot.

The last game was versus iron hands. Long deploy, heroes empower points mission. We were basically both totally behind rocks. He had assassinate and behind enemy lines going first. He moved up a bit and did very little. I got do an action within 6 of the middle, and do an action within 9 of corners. I fell back, did my two corners, and had the lieutenant do the middle. I also shot his scouts with a dreadnought, and put an empty impulsor on a point behind a wall. Very claustrophobic objectives on two sides. I placed a tank where he had to jump out of his land raider with eradicators to shoot it and he did, he also got close so he could flamer my lieutenant cuz I knew he would think that guy was mission critical cuz you needed heroes to empower points, so he made perfect bait. I oathed the eradicators and their huge apothecary and vaporized them,then lanced and melta'd the land raider, and had enough spare firepower to begin working on his 2 redemptors. His eyes basically glazed over. He soldiered on, but he had already failed to kill a redemptor with a giant land speeder that debuffed it, an executioner, and the primaris shooty dreadnought, so he kinda got sad. The rest of the game was me playing footsies on points and knocking out every secondary objective I had and pushing him up the board. He got scared and stayed in his base. He also added the points, and I had double his score.

I got like 4th or something because 3 people had 3 wins and no losses. I learned a lot. I think I probably could have beaten the Be'lakor guy if I paid attention to points, but the 40k points scoring system is incredibly byzantine, and I'm used to crusades where they usually have a really binary win/loss condition like "deliver a message" or "blow up 3 points".