Are fighter jets so important in the age of drones? Shouldn’t we invest in drones which are much cheaper? If “but we need something for air superiority”, then isn’t it achievable with space superiority and drones?
AFAIK: Militaries have done a lot of research, as you can imagine, and the overwhelming conclusion is that UAVs (unmanned aerial vehicles or drones) can do some things very well, some things not well at all - the truth of all technologies, once they shift from dream to practical reality. In almost all cases in the military (and probably in life), AI does better when teamed with a human. Particularly, AI does poorly in unexpected situations. Driving on streets with rules and lanes and signs is difficult enough for AI; war is chaos - the main tactic in war is overwhelming your enemy's decision-making with chaos. AI is too brittle; it can only handle what happened last time.
The widespread solution - I'm not sure about China and Russia - is teaming AI-controlled systems (UAVs in this case) with human commanders, so for fighter plane scenarios you get a human in a fighter plane controlling several UAVs. The US is just reaching the next development stage in this technology; look up 'loyal wingman'.
Sure it's possible to build a drone that can take off, fly to a designated point, drop some ordnance, and return. But we don't have the technology to automate complex missions like air superiority or close air support. Those require a human in the loop making real time decisions. If the human isn't right there in the airplane then the risk is that communications will be disrupted. In a major conflict with a near peer adversary, most of our communications satellites will get knocked out.