You're still pretty early - but you have the foundation of a solid non-unkillable team:

• Doompriest (debuff removal)
• Fatman (ally attack, DEF down, hp burn, poison)
• Ronda (DPS)

Things unfortunately start to fall apart at this point. You have nobody at all for protection, and you have nobody worth leveling for it either. You also have nobody with Leech, which is a pretty pivotal part of a team.

So, for now, I would probably just put Apoth and Scyl on the team, and just do as best you can. Don't worry too much about speed tuning or anything like that, yet. Keep your eye out for champs with Ally Protect and DEF up, specifically ones with 3 or 4-turn cooldown, 2-turn duration buffs. Also, look for someone with Leech. Here's a list:

https://ayumilove.net/raid-shadow-legends-ally-protection-skill-champions/

https://ayumilove.net/raid-shadow-legends-increase-defense-skill-champions/

https://ayumilove.net/raid-shadow-legends-leech-skill-champions/

For leech, you'll get Ghrush soon enough, but he doesn't bring enough value to be running with those above three I listed. In order to fit him onto the team you'll likely still need two others with DEF up and ally protect, so you may need to drop Ronda from the team - but we'll see when you get there.

On another note - you've done okay so far at not wasting time leveling bad champs, though you have made a few mistakes. From here on out, I'd highly advise you to NOT level anyone else at all, other than food for the aforementioned three champs to bring them to 60. Depending on what your team ends up being, there are a handful of 50s that may end up becoming 60 (Frozen Banshee being one of them), but none are guarantees.

Thank you so much for your help!