Can we set the percent of tax fee flexibly?

I am developing BEP20 token and I want to set the percent of tax fee flexibly.
for example:
I’m going to set tax fee for only sell
20% : 1 day after buy
15% : 2~4 days after buy
10%: 5 days after buy

that’s it.
but I am newbie in solidity and I have no idea to implement this.
Please help me.
thanks for your attention.

Have you tried to write this as code? We can help with specific Solidity and Ethereum questions. If you want someone to code this for you please post in the #general:developer-wanted category.