Honestly that's a bad idea. No one would have a reason to research and develop a new engine since everyone will run with the same one: the fastest.
Manufacturers love building their own engines and would keep doing so becasue of branding. But when you are enforcing engine performance parity and fixed price point it would prevent f1 from becoming engine dominated series while at the same those changes would allow basically every team to have totally unique engines. It is literally complete freedom to choose whatever you want. Of course in reality it needs little more detailed rules to rule out dangerous materials for fire safety and so forth..
Things would eventually converge towards more similar solutions and non-manufacturer teams surely would try to make sure they get the fastest engine. But I don't think it would ever lead to everyone using the same engine. And even if it would where is the harm? The engines are already very close to each other and the differences are rather minimal. And it has been this way for a long time. The v8 engines already were practically identical and the racing was excellent.
With this kind of engine rules we could see huge variety in engines. Some teams may go for fuel thirsty engines that produce more power but need to carry a lot more fuel. Someone might go for a light car. And someone goes between the two. Different circuits would suit different engines and you would have more winners. Also it would make the 3 tire rule per weekend more exciting as the softest option is not such a no.brainer as it is now. Heavier cars might prefer harder rubber for example.
The hybrid system in F1 is far from being a road car technology.
It is all about road relevance. Sure the hybrid tech requirements for f1 are totally different than for a road car but it is still all about putting road car tech into f1. Not the other way around. Not good for f1 because the hybrid engines are overweight and make the car slower compared to non.hybrid engines. Also more expensive, more complex and the grid is more locked down to different performance levels by ferrari and mercedes.
Refueling still means fuel management, so that's a bad idea as well.
Which is why I said no refueling...
Many people should start to realize that even though some things seem cool in their mind, in real life they can't work.
It is overly simplified proposition on my part and it is definitely not a complete one. Would it work or not? I think you need to provide deeper analysis than just saying "it won't work" without even giving any reasons why. And you have not even given any. Instead you address points I never made (refueling). Or address points that are completely the opposite what I'm suggesting (spec engines)!
F1 will never be a fair competition. The money spent are a lot and richer teams will almost always prevail. You can limit the budget, as they did, but not too much because f1 must remain the pinnacle of motorsport. If you want a competition where everyone has the same engine, just look somewhere else, this is not the place for you, it has never been.
I'm proposing completely free technical rules for engines and you say I want all cars to have the same engines? Did you even mean to respond to my post? I never even suggested limiting budgets either. Engine manufacturers could spend as much money as they want but they'd still need to sell their engines for 5 million per season to anyone who asks.
Last but not least, the sound is important but not as much as it is efficiency, durability, reliability. I wouldn't sacrify those for the sound. It's not worth it.
Sound, reliability and durability can co-exist. And the reason reliability is important is because of costs. But on its own reliability is meaningless.
The reason I did not mention any reliability requirements is because with the fixed price it is unnecessary. If someone can sell 30 engines per season for 5 million while other engine manufacturer tries to do it with 6 engines then let them do it. In the end the teams spend as much money in engines in both cases. 5million per season. This would also get rid of the stupid engine change penalties.