Mk-III we have already announced for launch for commercial launches. Next mission will be a commercial mission. That will carry a very well known OneWeb satellites, mid Sept-Oct this year and next year by January 2023."
Planned launches2022October - PSLV XL - Aditya-L1
2023 and beyond - GSLV - NISAR (NASA-ISRO SAR sat)
Come this October India will put one more of its rockets — the medium-lift Geosynchronous Satellite Launch Vehicle-Mark III (GSLV MkIII) — into the commercial launch market. Sometime during the third week of October 2022, the ISRO rocket will fly with 36 satellites of OneWeb, an Indo-UK joint venture satellite communications company, said an space sector official.
On October 22, India's heaviest rocket is all set to make its grand entry into the global commercial launch service market. In its very first commercial mission, the GSLV-Mk III will launch the British startup OneWeb's 36 broadband satellites from Sriharikota spaceport. The launch was made official by way of a contract signed by the Indian Space Research Organisation's commercial arm, the NewSpace India Limited (NSIL).
https://www.newindianexpress.com/nation/2022/oct/06/indias-heaviest-rocket-to-make-global-foray-on-october-22-2505380.html gives the launch time as 00:12 LT October 22 = 18:42 UTC October 21.