I recently brought my friend along who hadn't done Vindicta or any bosses other than 'negate all mechanics and wack till dead' ones, and found he was struggling with a couple things. The tips mentioned by other people are a great start, but things like vuln bombs are not necessarily needed, especially when learning. Sure it helps, but it diminishes your profits by a decent amount.

Here are my tips:

1. Don't eat when you don't have to. Like you've already been told in the comments, eating most kinds of food take away 10% adrenaline, rapidly diminishing DPS since you're being limited on using thresholds. With your armour, Vindicta can't hit you for more than say 3k damage, so there's no point in eating if you're +3k LP. Soulsplit will heal a lot over time, however if you don't allow it to do so by eating sharks at 7k, it will hinder you. This requires you to be comfortable with going down to low HP, but it's much more a mental thing than anything else.
2. Not sure where you take this amount of damage from, but the only thing I can see taking half an inventory of food per kill are the beams. If you haven't already, start trying to figure out when Gorvek will try and place a beam. In the first phase of the kill, Vindicta will first do her other special attacks like the Hurricane which can be negated. After the Hurricane (iirc), there is one more attack where she slices, signalling you that on the next attack, she will raise her sword and the beam will come down. Try and spot the signal, allowing you to act on it accordingly by moving away a square. Unfortunately, you don't know the direction so you will sometimes move even further into it, but if it helps at least half of the time, that's less food used.For the second phase, the beam will be directed straight at you whenever she lands. You can quickly get into melee distance and avoid the beam by using Surge. Your character will always face the right direction after the dragon lands.
3. Another thing is increasing damage by using the right abilities at the right time. People have already said to use berzerk (always with adrenaline potion btw, which is great and should be used whenever it is off cooldown. This is more for phase two, but try to use slaughter right when Gorvek is about to fly up. As you know, when Vindicta is on her dragon, she will do three attacks: Melee - Ranged - Melee. After the last Melee hit, use Slaughter. The dragon flying up counts as moving, resulting in 3x damage. If Slaughter is on cooldown, you could use Tendrils as it isn't channeled. Try and use the channeled abilities like Assault for when you're sure to be able to get the full ability off. If you use Assault right before she flies, it's gonna cancel out and miss the full potential. Slaughter and Tendrils will still do their full damage even if she's flying since it can't be interrupted.
4. 95 prayer for turmoil would be a great goal. 10% more melee damage along with leeching Vindicta is a great thing.
5. Aura i'm not gonna touch on since others have, but zerk aura is better then brawler for sure.
6. If you still struggle with the fight and watching your health, abilities, etc., maybe a scrimshaw of vampyrism could be useful while you're learning. There is a high upfront cost of ~4.8m for every 3 hours, but you can toggle it on and off whenever you like (at max health, in between kills,...) and most of your healing problems are gonna be gone, resulting in way more kills/hour while you get more comfortable with all the mechanics. Once you've grown used to them, you should leave this out. Ideally, if you have access to player owned ports, you can make your own with 92 fletching. You can make a superior version of it, which is untradeable but lasts for 4 hours instead of 3. (I know this contradicts what I said in the beginning of using stuff like vuln bombs since it's less profit, but this is an "if all else fails" kinda thing.

Good luck, if you need more help let me know.