LCA MK2 will be a total package. Compact yet packed to the brim. But Su-30s RCS will be very hard to hide. Nevertheless it can put the enemy fighters at a distance due to its payload and on-station time.
I believe Rafale-Tejas MK2 will be a deadly combination for the initial break the door kind of missions to PLAAF layered AD network than Rafale-Su-30mki. There will be losses. No doubt about that. That's where mere 36 numbers will bite IAF.
Su30mki will remain a potent beast. It has most weapons for sead and dead as of now including bramhos and rudram 1 along with all kinds of glide / long range bombs .
With upgrade it's aesa will be far more powerful than Rafale just because of sheer size of the radar. On top of that it will be GaN aesa Making it even more potent.
Being dual seater most mki will be mated with CATS program and control cats hunter / alpha S and cats warrior suside drones to breakdown enemy air defence from standoff distances. This capability will put it far ahead of Rafale as force multiplier.
Then there is report of growler type su30mki for electronic warfare which will be able to mask entire attacking party and jamming enemy radars from long distances.
Many indian ew pods are already being developed including Siva pod , HBJ pods along with Russian and Israeli pods availability.
That's why there are still consideration about buying more mkis. .
It will rule the sky's for a long time to come and it will be fully used in sead and dead missions with powerful standoff weaponary and potent ew jammers.