Unfortunately you will most likely need a Snapdragon phone (there are affordable phones that have Snapdragon 665 such as Moto G8 Power or Redmi Note 8T. Snapdragon 730G phones should also be affordable). Mediatek have poor drivers, that is why it’s very slow.
Ideal would be Snapdragon 855 or better, the new Snapdragon 888 is a beast from what I have heard but it might be out of your budget.
Be careful if you are going to look for Samsung phones as they can have Exynos instead which are also slow on Citra right now.