I chose to play a Githyanki warrior as the trailer suggested intrguing Mindflayer storyline action in Forgotten Realms once again. This player character choice made me unable to recruit Shadowheart as she distrusts and attacks me on cultural bias. I knocked her unconscious as she choses to attack me. Left her for good stripped to the leather bikinis as I wanted to preserve any survivors knowledge she may have. On this choise you can recruit her only after meeting her again in the Druids cove. Which strips you form access to her healing and protectuion spells for this fight, the extra actions and HP pool.

So this can even be won solo easily enough. Stop the whining pls. as there is much harder fights with full team to come.

Ensure to avoid the disadvantage of multiple strong opponents by all means. Avoid anything in your back or side get huge boni. Exploit that for yourself and don't fight stationary when not to your advantage.

I did shoot the short bow and ran several times. One blow finishes the leftovers easily enough when they manage to attack alone close up. No sneaking, shooting barrels, dipping arrows or companion needed for this. Just brute force and footwork did it for e alone. Do whatever the strenght of your character are. I didn't even use sprint to create more space.

I my eyes this fight is intentionally a challenge with an upfront warning to teach you all the depth of D&D tactics available and realize the benfit of seperating enemies before they gang up on you,

In my eyes this fight is amazingly well balanced for anything you throw at it. I needed only a second or third try when my frontal assault and belief in my warriors superiority alone was refuted by the game. So I took the hint at face value,
Turn based RPGs save & reload is a common and unavoidable concept. have no objections to utilize this.

One key concept of D&D is armour class. If your character doesn't bring it along, stay strictly out of close combat and use any spells that helps boost it. Eventuallyyou got to reload due to your boost roll fizzle on low RNG alone here.
Get a feeling for what you armour can or can't do for your HP churn rate against each enemy you meet. Adjust your tactics to it.
It also helps to right click and review for weakness and resistances to adjust weapon sets and tactics.
Concealment and initiative may also be an asset for a skillbased deadly blow opening attack as well as haste, potions, throwing things or any consumables. These are very character specific to learn and explore.

Make sure to adjust you spell choice for the task and rest to memorize them for the day to come.

For a rogue or low level mage this will be a tough solitary fight on low armour class and still missing spells or rolling low on damagea lot. The real questions is, how many player character options do deny you to recruit Shadowheart? None of these choices will not fight this alone due to the Shar affiliation of this cleric being really ideologically flexible apart for dedicated extraplanar mindflayer hunters.

I found a level 1 and 2 Gale being wiped by Goblin bows and area effects way more annoying many times over. There should be a checkbox to auto-cast mage armour when this guy even just get's out of his sleeping bag.
That's where I found the Fog spell not safeguarding and hiding him at all and being entirely useless atm. Some area effect based spellcasting clearly does need further review by Larian.

Trying several tricks and options plus keeping a distance should get you through this one easily enough. No matter what you bring to this brawl.

Never deny a DM your best game night cookies. Complain at your own risk.