Season the meat with salt and pepper and, if necessary, cut in half so that it fits.
Place the stainless steel inner pot inside the Instant Pot®, press Saute, and set time to 25 Minutes.
Add the drizzle of olive oil along with the meat and brown well on all sides. When ready, remove and set aside.
Add the onion, carrot, celery, and rosemary. Sauté until the onion is soft and translucent. Add the vinegar and mix. Once this is done, press Cancel.
Add the meat, broth, and soy sauce and mix.
Close and lock the Instant Pot® lid. Make sure the steam release handle is turned to Sealing. Press Pressure Cook pressure level High, and set time to 1 Hour.
Once the time is up, press Cancel and turn the steam release handle to Venting. Once all the pressure has been released, open the Instant Pot® lid and stir.
Remove the meat and blend the rest of the ingredients.
Return the sauce to the Instant Pot and press Saute. Set time to 10 Minutes, let the sauce thicken a bit, and check for salt.
Cut the roast into slices as thick as you choose using an electric knife.
Lastly, top with soy sauce and serve with mashed potatoes and rice.