Theoretically, if the enemies are the same level as you then you should be able to win against them (regardless of their abilities). That's how most video game systems work and I assume what Larian is going for. Of course, this is EA so all the fights aren't necessarily calibrated correctly. (Larian, if you're reading this, I don't think the gith fight needs to be changed. Some fights should be very difficult)
The gith fight in particular is a difficult one. Party positioning before the fight isn't necessarily cheese. You know that some enemies will misty step to high ground, so if you place one of your characters there that will help (I like Gale + Thunderwave). Consumables like potion of speed can help a bunch. Focusing down the more powerful gith is necessary.
But honestly this fight is probably balanced around using at least some level of cheese: backstab & high ground advantage, jumping, BA shoving, etc. If you're not using those then it'll be pretty tricky.
Edit: I feel like you can't use 5e sources to estimate encounter difficulties simply because so much is changed (for better or worse) between 5e and BG3
Last edited by mrfuji3; 09/04/21 05:46 PM.