Combine chicken stock, gelatin, tomato paste, soy sauce, fish sauce, and Worcestershire sauce in a blender. Blend on high speed until combined. Set aside. 

In the pressure cooker, heat oil over medium-high heat until shimmering. Season beef chunks with salt and pepper and add to pressure cooker. Cook, turning occasionally until beef is well browned on 2 sides, about 10 minutes. Transfer beef to a large plate and set aside.

Add mushrooms to pressure cooker and cook, stirring, until liquid is released and mushrooms begin to brown, about 6 minutes. Lower heat as necessary to prevent scorching. Add chopped carrots and pearl onions and cook, stirring, until well browned on all sides. Season to taste with salt and pepper, then transfer to a bowl and set aside.

Add halved yellow onion to pressure cooker, cut side down. Add 2 whole carrots, celery ribs, and garlic. Cook, turning carrots, celery, and garlic occasionally until all vegetables are well browned, about 4 minutes.

Add wine, scrape up browned bits with a spoon, and cook until reduced by three-quarters, about 3 minutes. Add reserved stock mixture from step one.

Toss cut seared steaks with flour. Add bay leaves and thyme sprigs. Stir to combine, seal pressure cooker, and bring to high pressure. Cook for 30 minutes, then rapidly release pressure and open cooker.

Remove whole carrots, celery, thyme, bay leaves, and onion. Add potatoes and reserved sautéed mushrooms, pearl onions, and carrots to stew, reseal cooker, bring to high pressure, and cook 15 minutes longer. Rapidly release pressure.

Stir in peas. Season to taste with salt and pepper if necessary. Serve with cornbread muffins.