Finished the main campaign last night, with a few side quests remaining.
The final level is a slog and a half and goes on for a good while, I was getting fatigued fast. This resulted in me getting my rear end absolutely handed to me by the final boss. If like me you're rusty with high speed fights, you'll struggle. I expended a ton of resources only to see that effort wasted by those structures that replenish machine health.
To be honest, I was tired and I rushed into battle without even analysing the body structure of said big bad. I could have taken it down easier but it all went wrong fast and the entire battle was about 10 minutes long I kid you not. In the end I ran seriously low on Blaze so be sure you're armed to the teeth with that and Chillwater before taking on the last mission.
Overall I haven't been too impressed by Frozen Wilds. Then again I'm not sure what I expected and I had done very little reading on the DLC prior to release. I was expecting more machines, and whilst we did get a few, we also ended up with the old ones and an irritating form of Corruption. The lands whilst beautiful to look at become tiring after a while because of the constant snow. Credit to GG though - they designed the new landscapes and its old world structures really well (Montana Recreations!).
The main campaign seemed rather boring, whilst the sidequests and random exploration was still enjoyable. It was great to see Aloy back again though. Despite my comments I thought the DLC was easily worth the price.