As per the Aeronautical Development Agency's head's latest interview from January 2021, Tejas Mk2 prototype is planned to be rolled out in 2022. Metal cutting is to begin on the prototype in February 2021. But you'll get more confirmation on this in a couple of weeks from now, once Aero India 2021 starts.
The Tejas Mk2 is planned to be inducted by 2026. Add a year or two depending on how confident you are about their schedules.
They are very clear that the fundamental technologies are all now proven on the Tejas Mk1 and almost all are developed within India even if they took foreign consultancy to fix issues. The FCS, composites, avionics, the Mission Computer, weapons algorithms, the fuel management system, the brake management system, you name it. Plus, the indigenous Uttam AESA radar is doing very well in flight tests from what I gather. So it'll replace the Elta 2052 that's there on the Mk1A.
The Tejas Mk2 just adds a bigger airframe and engine and needs to be designed to cater to that. It is THE fighter that the IAF is most interested in as of now, since it'll replace the Mirage-2000, MiG-29 and Jaguar.
Just FYI, the ADA Director also said this about the AMCA (which is now in detailed design phase)
" India is aggressively working on developing its 5th generation advanced multirole combat aircraft (AMCA) to reduce dependency on foreign players and support the ‘Aatmanirbhar Bharat’ mission. Could you share the latest updates of AMCA project?
AMCA is India’s ambitious 5th/ 6th Generation aircraft program. The feasibility studies of AMCA were completed in 2015. In 2019, IAF gave a formal go ahead for development of AMCA in two phases. AMCA Mk. 1 would be developed with an existing engine while AMCA Mk. 2 would have an advanced indigenous engine. Moreover, AMCA Mk. 2 would have 6th Generation capabilities. Today, the AMCA configuration has been frozen along with the architecture of all the systems. Detailed design has commenced and roll out is planned in 2024. "
Again, add 1-2 years to the current roll-out date mentioned if you feel like, but still we're talking about 2025-26 for the AMCA Mk1 with 2 X F-414-INS6 engines.
Also, FYI, ADA is going to reveal the FINAL design of the Tejas Mk2 and AMCA as well as the Preliminary Design of the TEDBF at Aero India 2021. I'm personally very very interested to see what they show. Especially the TEDBF which is very likely to be different than the Tejas Mk2 and instead based on the LCA Navy Mk2's final design before the Indian Navy dropped the single engine LCA Navy Mk2 fighter. So, basically a twin engine evolution of the design shown below.