Hello,
is it possible to make the car bonnet/hood using the hand lay-up technique or if there is too many surface details on the car bonnet for the hand lay-up technique?

thank you and have a good day

It is possible, but it is not ideal in my opinion. The details are usually not the problem. But it is almost impossible to get a really good surface quality over such a big area with simple wet layup. You will likely need many clearcoats, and lots of sanding to get a good finish. Sanding, at least for inexperienced users, can screw up the whole part, or at least the visual perfection, if you send into the fibres.
considering all the work and money for the mold and the material, a 100 euro or even less rotary vane pump, and 25 euros for bagging material and flow media always would be worth it in my opinion. With resin infusion you could easily save 2 days of work, and get a better part out of it.

If you are planning to use vacuum compression, the step up to resin infusion is practically a no brainer.
And if you haven't got a random orbit sander, you might save this investment when using resin infusion.