The problem with Ogryns is that they need a babysitter. Their Ld is too low, a round of bad shooting for you and they're gonna run away. The Primaris Psyker is perfect for this role, give the squad already stubborn a pretty good Ld and is in very good synergie with his shooting attacks. I use them usually in units of 3-4 with the Psyker in a Chimera (12" range is not great without transport)

Your HW teams are also only Ld 7, nearly half of them will fail their orders. What about a Lord Commissar bubble next to the Lascannons?

Blob squads work very well in squads of 3; bbig enough to be powerful, not too hard to move. And you need special weapons: plasma gun personnally, but melta is great too.

Small Special Weapon Squads are a nice thing to add as well. Hide them and when the ennemy gets close jump on them with flamer and two demo charges !