No, not true...
Knowledge and experience are accumulated over long and painful
years. The Americans, Russians, British and French did not just
learnt to design advanced jet in a short period of time. They have
been doing that since the first jet was built after the WWII.
Yes, ST Aero has learnt fast, fast track their knowledge and
experience but they are not even near where the Japanese, Koreans,
Taiwanese, Israeli, Indians and the Chinese are today. These
countries set out to build some of the most advanced aerospace
industry. ST Aero is at least 1/2 a decade behind these countries
in terms of the technical capabilities (a credit to ST Aero itself
already given it got nothing much to start with and have achieved
so much in so little time). To counter your statement, Rome was not built in a day
and ST Aero or Singaporean aspiration of building a locally
designed fighter is a case of the heart is willingly but the body
is NOT.
Is ST Aero insists on building a locally designed fighter, it would
at best be a design copy of a third generation fighter (albeit it
could have the best avionics), but lack critical advanced
aerodynamics design and capable FBW controls. That is for sure.