You can try and build your Dessert Queen to 6 star, and let it push the game higher for you.

Then, you can go farm for Light Inugami, and train it to 6 star

To do Halls B10, if Giants, you need to build Wind Pixie Shannon. If other halls, you need to start looking for materials to fuse a Veromos, and Fire Sylph.

I would suggest to build your GB10 team first since you basically have all the needed monster to complete GB10
Shannon, hathor, bernard, yen , Rakaja. Or you could replace rakaja for better healer in case you got better healer on the process of building your team.
Your team doesnt necessarily need to be all 6 starred, as long as your monster can survive few hits from the crystal on earlier stage it would be fine. Boss stage would be easy with shannon & bernard buff/debuff.

Giant B10 is relatively easy compared to Dragon and Necro B10, when you have good enough rune and sufficient amount of 6* monster that is the time you build your team for other cairos dungeon.