The Instant Pot does an okay job sautéing and browning. You can choose to use it for the bacon, beef, carrot, onion, and garlic if you like. I prefer to use a large, heavy frying pan on the stovetop.
Dry the beef cubes well with paper towels.
Using the IP sauté function (on high if your model has an option) or in a large frying pan on the stovetop, cook chopped bacon, stirring from time to time, until browned. Remove bacon from pot, leaving fat in pot.
In batches to avoid crowding, add beef cubes and brown well on all sides. Remove beef from pot and pour off (or spoon out) all but 1 tablespoon of fat.
Add onions and carrots to pot. Cook, stirring from time to time, until becoming tender and lightly browned, about 10 minutes.
Add garlic and cook, stirring, one minute more. Stir in tomato paste.
Pour in 1 1/2 cups (375 ml) wine and 2 cups (475 ml) beef broth and scrape up browned bits from bottom of pot. Stir in thyme, bay leaves, 1 teaspoon of the salt, and pepper.
Add beef and bacon back to pot. (Or, if using a skillet, pour all contents into Instant Pot.)
Position lid seal vent. Cook on manual, high pressure, for 20 minutes. Let pressure release naturally.
While stew cooks, set frying pan over medium-high heat and pour in olive oil. When hot, add mushrooms and remaining 1/2 teaspoon salt and cook, stirring occasionally, until well browned.
When pressure has released, carefully open Instant Pot and set to sauté. Stir in mushrooms and defrosted pearl onions.
In a small bowl, mash together the butter and flour with a fork to form a paste. Stir paste into stew.
Simmer for 10 minutes.
Remove thyme stems and bay leaves and stir in parsley just before serving.