Keep in mind that these 20% aren’t spread across the whole population, contrary to VAT for example
If you did away with income tax you’d still end up having to modulate another tax according to income/wealth, which kind of ends up being the same thing as an income tax
According to this, Finland's budget revenue for 2021 is estimated at €68.1 billion. €14 billion of it (20%) came from income and wealth taxes.
Your excise taxes alone are almost half of what income and wealth taxes bring in. VAT is 31% of the budget revenue.
With numbers like these I don't think it's unreasonable to do away with income taxes and replace them with other forms of taxation.