Are you saying Congress should be domain experts every area they allocate funds to? From maritime safety to preschool nutrition, congress should be expert enough in everything to specify all important details, and then the agencies (staffed by actual domain experts in each area) are mere accountants to execute the policies?

I don’t think it’s workable. At best it just swaps lobbyists for civil servants.

More realistically you'd end up with an official advisory body where the exact same experts would write the regulations, they would be intermittently passed by congress between their regular bouts of systemic dysfunction, and the current crop of bureaucrats would be replaced by mindless pencil pushers. Add an official title for members of this government run advisory body such as "sage" and give them lifelong tenure and we've about completed the process.

On paper it's different but in practice congress would largely be rubber stamping things. I predict the differences would be largely negative. More room for non-experts to meddle, more room for lobbyists to insert themselves into the process, and more room for broad capture of the advisory body to go unnoticed.

Ostensibly, who's paying their salary is important. Lobbyists, paid for by corporations with a vested interest in things going their way, is far worse than civil servants who's salary comes from taxpayers, and who's responsibility is to them, and not corporate interests. Ostensibly.