Most universal remotes should be programmable to the TV. Or get one made for your model from eBay or Hisense support. I don't see a manual or images online of the TV where you can see if there are buttons, but there should be volume and input controls on the TV, they may be on the bottom / side hidden as touch buttons.
Another option is to get a soundbar or speaker with optical input, connect it to optical out on the TV and use the speaker remote.