Set the Instant Pot to sauté function and set the time for 15minutes. Add the oil and sauté the bacon until crisp and browned then set aside.
Add the beef to the inner pot and sear until browned on all sides in the oil/bacon fat.
Return the bacon to the pot. Season with salt and pepper. Sprinkle with flour, toss well and cook on sauté for a further 4-5 minutes to brown.
Add in the onions, carrots, wine, 2 cups of stock, tomato paste, 4 cloves minced garlic, and herbs. Stir well with a wooden spoon and deglaze the bottom of the pot. Secure the lid and press cancel to stop the Sauté function.
Select Pressure Cook on high pressure for 30 minutes, then press start.
When the cooking program has finished, allow the pressure to release naturally for 10 minutes then quick release any remaining pressure.
While the steam is releasing, prepare your buttered mushrooms: Heat the butter in a medium-sized skillet/pan over medium heat. Add the remaining 2 cloves garlic and cook until fragrant (about 30 seconds), then add in the mushrooms. Cook for about 5 minutes, while shaking the pan occasionally to coat with the butter. Season with salt and pepper.
Press cancel on the Instant Pot and select sauté again for 10 minutes. Add the mushrooms and let the sauce simmer and thicken.