I only just got mine, but I bbq a lot so am used to fire management. Here is your checklist:

1) Tent vent - more open = more oxygen for your fire (more heat, especially if the ambient outdoor temp is not cold)

2) Stove vent - same concept, fully open vent = more oxygen = hotter fire. Note that even in the guide they say you can partially pull out the tray where the vents are to give it even more oxygen (havent tried this).

3) Type of wood - not all wood is created equal. The birch they sell burns lower BTUs than the hottest burning woods (common in the US): hickory, oak, black locust, and ironwood.

4) Amount of wood. If you are not filling your stove (~4 pieces for me) then you have opportunity to add more to increase the heat.

4) Make sure your chimney is clean. When you see the draw outside at the top of the chimney it should be almost invisible smoke if your fire is burning clean/hot. If you see much smoke after the logs are lit and burning well, something with your fire/fuel source may be a concern.

5) For startup, keep the door open until the wood is burning well before closing it.

Also you could consider adding more “heat sink” items that will absorb and retain heat, then radiate it. This can be more rocks or metal. They sell large basalt tiles, I was considering those as an option to increase the temp but havent pulled the trigger yet.

Also keep in mind the temp from top to bottom of the tent will vary by ~10 degrees or so.

I've found the thermometers & hygrometers provided are not very accurate. I would suggest a different thermometer to choose.

FWIW, I always keep my vents all the way open, both on the stove and the one on the tent.

Does your stove ever start to glow? It should be kept to a minimum, but that is a way to tell if if the stove itself hot.

You might have that tent vent open too wide.