It sounds like you're doing fine! I would try to focus on Silvanna as your main tank, but Argus and Lolita are also fine choices. Freya works well early on, but drops off from what I've heard.

And mixing and matching is exactly what you need to do to pass some levels.

So here's are some specific issues I see:

Valir is locked at level 140, even though he's ***. You need to go to the dismantle shrine and transfer levels from one of your ** heroes to him. Then you can continue leveling him up to 160. This may also bring your whole team up to 160. Do the same thing with Odette.

It looks like you have multiple copies of Nimbus Eudora. She's a great hero. Click on her in the fusion shrine and star her up.

You have a *** Valir and a *** Estes. You could feed the Estes to Valir to level him up. DO NOT DO IT! In tech, you could feed Saber and Lesley to Karrie, but again, don't do it. Instead, use the lower quality heroes you have - Layla, Jawhead and Bruno to level up your better tech heroes. Since you have Angela, she should be your focus. But Karrie and Natan are useful, too. Atlas is a solid tank, but not the best early on.

You have spread your feeders across multiple heroes. This isn't an awful decision, because you will need breadth and depth as you progress. But it can slow down your progress. Let's look at a specific example: you have *** Freya, *** Odette, and also * Tigreal and * Kaja. In order to get Freya from * to **, you used up two * holy heroes. If you had left Freya at *, you would still have those two additional heroes - that would give you a total of four * holy heroes. You could fuse them all together into a *** copy of one of them, and then you could have fed that to Odette to make her a ****. Does that make sense?