We have 3 instantpots (yeah, no comment needed)
We bought the original back in 2015 ish (8 litre) because we cooked a lot for our boxer dogs for a healthier diet than can junk, liver heart, gravy etc, they insulate well (as you are aware) so excel in terms of a low energy cooking option, then we realised that we needed one pretty much just to batch cook for the dogs never mind us.
Wandering around costco the other year we found the 8 litre version that comes with two lids (one being an air fryer) which does work well for browning a chicken but not an xl bird due to the inner air fryer holey pot that sits within the s/steel inner greatly reducing it’s useability as a general airfryer, & whilst it did (removal of af inner) accomodate & brown the top of a chicken, without the proper lift (yes the trivet does ok) it is still better off finished in a small airfryer for 17-20 mins (wife bought a hypsantia) because we simply do not trust the anova ovens performance nor durability, nor service, nor app, too many angst ridden posts of problems resulting in a junker or anova sending another oven out… cost prohibitive therefore in the uk, a mass of slow to fix physical design problems etc (sorry to say)
So we use anova SV wand (well I have a few) stuck on a spare 8 litre instantpot inner with a silicone lid for insulation & tight sv stick cut out, water stays in for a week (unless garlic tainted) then used elsewhere if possible (plants, mop & bleach bucket) etc
The pot has 50+ mm of foil faced (complete wrap) to sit on & then the same on the sides, this makes it very efficient in terms of thermal losses, far more than a mere towel wrap.
The point to consider with a water immersion SV stick is that the water will sit at say 23-27c (uk summer) & the remainder of energy to get it up to steak / chicken temps is minimal, as is the dwell time potential for cooked product eating later than anticipated.
Whilst it is another piece of kitchen kit, I find being able to run 2-3 energy efficient items to put a supper together easier to bring together.
The sv stick is superb for eggs (tasty proteins) & whilst I tend not to care about “snotty eggs” if you were to do a decent soft boil it is advisable to do the 3 min boil (induction hob for efficiency) before banging it in sv water for 45 mins, …they stay good all morning if left for a “when you want to eat, eat” delayed scenario, an sv wand also helps make a decent poached egg with minimal water swirling (protein losses) in a pan if serving to someone who is precise & particular.
SV wand really useful running with solar for keeping energy spikes / draw to a minimum,
Sadly I don’t get too adventurous with veggies as I tend to hammer lentils & rice done minimalist, & fish aplenty, the odd steak, veggie burgers (beyond beef) which drew our family unit into preferring them to minced beef burgers, though I will more or less hammer a whole head of steamed broccoli added to rice & seasoned with a decent furikake, soy sauce & kadoya toasted sesame oil (pure, japanese)
Sadly had a very bad early veggies relationship that I continue to strive to get to grips with cauliflower, …split & baked aubergine halves was my most recent win! which I must practise on.
No idea how haggis cooks in the anova oven but again for dedicated sous vide this type of dense foodstuff “puddin” is another one I cannot leave unfinished, “everything bar the BAAA” that I often have ready to go, never even gets to see a frying pan. I have yet to try a vegan haggis type thing but never say never!
I wish you luck with the oven cooking endeavours.