Welcome to the forum!
Have you chosen a specific font? If it were me, I would start with choosing a font, because of course there are different ways in which 5s and 8s can be depicted. Like for example, they could be very blocky and heavy looking, or very thin and light. In some fonts the characters have the same width along the lines, and others are wider in some place and thinner in others. And then there serif or sans serif to consider. Many choices!
After I chose a font and typed the numbers with the Text tool, then I would overlay them.
Then Path menu > Object to Path, and switch to the Node tool. This is the part where you might want to smooth out the corner on the 5.
Or it might be possible that you can find a font that works almost perfectly without any node editing. There are SOOOO, so many fonts out there - and certainly no shortage of free fonts!
For myself, I would probably use node editing with the Node tool. But you could try some LPEs, such as Bend or Lattice Deformation or Envelope Deformation. Those all allow you to bend or warp objects or parts of objects. After the bending or warping, be sure to use Object to Path to convert the results back into regular paths.
Out of curiosity, do you have a plan to make it so that the modified 5 doesn't look like an S ?
