The F-35 program is more akin to the Eurofighter program. Always an issue when you have multiple fingers in the same pie. Trouble is all countries have their own unique OCD and then expect a single platform to fulfil it then as was the case with Eurofighter you had certain countries, e.g. Germany, steering it in their direction.
The UK had a good reputation for design and building aircraft but then they closed that industry.
To understand product creep and cost blow out in defence (I will not spell this word with an 's') Projects I recommend you watch Pentagon Wars. It is mandatory viewing for ILS specialist in Defence.
https://youtu.be/6jT-PzCWyy8