I think representative democracy is fine, it's career politicians I'd do away with.
The term for this kind of election is sortition.
In general important decisions require many different skills.
This will also lead to the problem raised earlier of experts making decisions that suit their own interests (and biases).
I’m pretty sure you’re not serious in suggesting a technocrat class who are sheltered from the real world, but let’s assume you weren’t. The end result of this is likely to be stagnation because you lack the introduction of new people and new views into positions of power. I’d also add that in a functional government we already have that class of people who are purely focused on implementation and looking at options in the Civil Service. Rarely is a cabinet minister themselves really coming up with ideas, they’re waving their arms and describing vibes to the Civil Service, who then go and work how they’re meant to achieve it.
Unfortunately for the last 14 years we’ve had a government asking them to do ever more unhinged things, with predictable results.
This is especially true when the "science" they are supposed to study is economics, a notorious pseudo-science whose real purpose is to act as justificationa for policies desired by whoever is paying the research.
There is no way to ensure that rulers align with the people unless the people have a say in who rules. Scientific authorities have a long history of being negative even for their own fields ("physics advances one funeral at a time"), and that doesn't change when they are given power over an entire country.
This is really simple political theory, not some advanced concepts.