Yes, the FBI should be completely eliminated. Put the FBI Lab with the US Marshalls. Outside of the DOD, no federal employee other than US Marshalls should be allowed to carry firearms. The Secret Service should be under the Marshalls.
But the democrats needs their storm troopers
While I understand your position, there are some fed LEOs who need to be armed. The US Border Patrol and Customs come to mind as their duties were enshrined in the constitution.
Why say the Interior Department, Educations Department, the IRS and USFS have swat teams bogles the mind.
Part of the FBI's problem is the extreme centralization that took place under Bush and Mueller. It was formalized as the Deep-State's political DC police force.
One simple change - Take away the FBI's guns. If it needs to take down a group of armed bad people, force them to coordinate with local police and their weapons, or the US Marshals.
Better, but the head of US Marshalls is a Dem now.