Though, as Trump correctly pointed out, you can’t get rid of the IRS completely—because someone has to collect the taxes.
The United States existed as a Constitutional republic for 125 years without the IRS.
I say completely deconstruct and de-charter the Agency. Ditch the entire current tax code - all of it. Fire all who worked for them and hire new from industry. Re-invent the tax collection system from the ground up in an entirely new environment. Create in its place a new zero-based Agency that has to justify every cent of its existence. Re-hire no one from the former IRS.
FReegards!