It took me 17 years to go from no stage to stage 4. Do what ever you can to reverse your condition.
I would assume it is different for everyone
Try to find what is causing it and try to fix it
It is not a nice feeling in stage 4 with all the other health conditions that you get later in life.
“ Liver fibrosis is the final result of most types of chronic liver injury. Most habits and events that injure the liver will lead to a fibrotic liver. ... There is clear evidence, based on findings from repeat biopsy, that mild to moderate fibrosis is reversible.”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3995196/
Fibroscan results range from 2.5 kPa to 75 kPa. Between 90–95% of healthy people without liver disease will have a liver scarring measurement less then 7.0 kPa (median is 5.3 kPa).
Just for perspective, your score of 8.1 is only slightly above what a healthy person with zero liver disease would have.
With treating your hep b it is likely you will not progress further and could experience improvement to F1 or even F0