Yeah but i've known some people paying like $20 per tx which is ridiculous! That's why i made this guide

First of all you should never report bitcoin transaction fees in terms of fiat or even in terms of bitcoin. You should always report them in terms of bitcoin per size (sat/vbytes) because the raw values in fiat or bitcoin are meaningless.
For example in normal circumstances with fees being around 4 sat/vbyte a simple transaction with roughly 30 multisig inputs would require $20 at about $41k bitcoin price.
Your title is also wrong since you include the term "withdrawal" which is the act of taking money out of an account and whatever fee you pay there has nothing to do with bitcoin or its transaction fees.