Wrong. Many (probably most) conservatives want to greatly reduce the complexity of the income tax for many good reasons:
https://www.propublica.org/art...
Oct. 1, 2018
Starting in 2011, Republicans in Congress repeatedly cut the IRS's budget, forcing the agency to reduce its enforcement staff by a third.
The IRS is incredibly efficient at bringing in revenue. The more money you throw at the IRS, the more revenue they bring in.
So naturally, because of their ideological opposition to taxes, Republicans have been massively defunding the IRS since 2011.
Unsurprisingly, this creates massive deficits in the Federal budget, which is something that Republicans are ostensibly against.
Fully funding the IRS would close the budget gaps without any other action by Congress.
Republicans could have their cake and eat it too, without being seen to raise taxes.