If Tejas had an Indian engine instead of an American one, it would sell exceptionally well. I compared its specifications to other 4th generation fighter jets and found it to be the best among 4th generation fighter jets. Additionally, Tejas MK2 is expected to enter service by 2026-28, but unfortunately, it is also equipped with an American engine.
1. Specs do not mean everything. In fact it often means very little apart from forming some basic understanding of the
range of operative parameters the aircraft handles.
2. Reported specs (yours and everyone elses) are often intentionally quoted. Only when it comes to selling do more details (far from all unless a non-strategic fighter sale and a non-strategically important aircraft) become divulged and only under controlled circumstances. Surely with many NDAs signed.
India can pay Safran for a back-up engine tailored for Tejas, based on M88 engine. If India feels the need for a non US backup due to political pressure and anticipation of future "issues" in dealing with the US.
Assuming engine isn't an issue at all for India and any potential customer of Tejas, it is still quite a stretch to assume it would be an export success. It would be competing with high end, combat capable trainers, second hand, aged F-16s and Mig-29s and also of course the JF-17 block 3 (since that is the block for which manufacturing is being tooled). No way to tell exactly how these really stack up even if we ignore tender politics in any hypothetical tender situation. Any conclusive attitude can and should be chalked up largely due to the opinion maker's national biases.
If we are to compare Tejas MK1 paper specs to these other low tier fighter products, it certainly appears to be a decent competitor and within the general specs of these others on paper. The detailed performance of each subsystem is where the real gist of the fighter's overall capability can be found and none of us talking on the internet know well enough.
I often find that online Indian nationalists (a lot of them and that's now even clear to Anglos lol) claim that Uttam radar is the be all end all of AESA tech ... which btw is aged tech already and multistatic radars are the new unmentionables until China or the US field them and adversary party start talking more. The facts are, India has not fielded any domestic fighter (or indeed airborne) AESA. Uttam is India's first attempt and first generation. JF-17's radar is much more an afterthought compared to PLAAF's own domestic fighters I admit but JF-17's blk 3 AESA unit is at least a second to third generation. Talking beyond these basic facts where each can draw some of their own conclusions however biased, is honestly going to be inviting the usual talk from the type of people who claim India's version is automatically the best ... because ... inkredable India.
Also for the MK2 Tejas I'm assuming is the one where they include canards into the design, would be not that much better in kinematic performance to the other existing delta (and cropped delta) canards. American engines for the MK2 should be considered a plus. The F414 is an excellent engine. What you lament is the potential for export blocks and the US being able to pressure India using access to purchasing this engine as some political leverage tool. In terms of performance, it's pretty damn good even for 2030. Of course mid thrust engines in that time period will include a few newcomers making use of some newer tech developed after year 2000.