Pat chuck roast dry. Season all sides with 1 teaspoon salt, pepper, garlic powder, onion powder, and thyme. Rest at room temperature 10 minutes.
Heat olive oil in a large skillet over medium-high heat. Sear roast on all sides until deeply browned, about 2 to 3 minutes per side. Transfer to a plate.
Add 1/2 cup broth to the hot skillet, scraping up all browned bits. Simmer 1 to 2 minutes and remove from heat.
Place potatoes, carrots, half the onion wedges, and garlic in the bottom of the slow cooker. Set roast on top. Scatter mushrooms and remaining onion around the roast.
Whisk together remaining 1 cup broth, Worcestershire, tomato paste, soy sauce, remaining 1/2 teaspoon salt, and deglazing liquid. Pour around the roast.
Cover and cook on HIGH for 2 hours, then reduce to LOW and cook an additional 3 1/2 to 4 hours until roast is fork-tender.
Transfer roast and vegetables to a platter and tent with foil. Skim fat from cooking liquid. Pour into a saucepan and simmer uncovered 10 to 15 minutes until slightly thickened. Stir in butter and a splash of Worcestershire or balsamic if desired.
Cook egg noodles in well-salted water 1 minute shy of package directions. Drain and toss with butter and 2 to 3 tablespoons of finished sauce.
Shred or slice roast. Serve over noodles with vegetables and sauce spooned over everything. Garnish with parsley if desired.