Lets try to walk before we run.
I am willing to bet BAF is so far gone that any jump to 5 gen is ridiculous.
Probably should start with basics and overhaul entire force.
Politics will dictate what platform is eventually acquired but 4.5 gen much better idea as of now. i.e. J-10C vs F-16V or a euro-canard.
Of more importance is to change the culture and improve recruitment and training.
BAF will always be a generation behind then against neighbours.
You can be sure by 2030 the junta next door will get J-35A.
I don't understand this logic of you need 4th gen before 5th gen?
This is not like a course in mathematics where each course builds on the knowledge of another.
Yes it will take longer to operate fully than say PAF but so what? 18 to 24 months of extra simulator, jet trainer and tactical training is not much when you buy a fighter plane for 25-30 years.
BAF pilots can be taught by both China(manufacturer) and Pakistan(primary export customer and more experienced airforce).
The issue is not complexity but BD willingness to invest in the platform, infrastructure, associated systems and training to fully utilise a fighter like J-35A.
In theory you can equip a newly created country with zero aviation experience with F-22s and teach them over many years to operate the plane as well as USAF.
Anyway BD has operated 4th generation fighters for over 2 decades now and so technically it is not skipping a generation.
It can only afford small numbers(~100) of fighters and so should go for the best it can buy.