Your epoxies are going to become soft well below temperature of burning plastics or oil. That looks like fire damage. Something in the mixture makes their carbon fiber burn. It’s not inherent that carbon fibers burn.

I would think any fifth generation design at MiG-35 weight class would need to be targeted at a price point to make it the main fighter of the future for the Russian Air Force and Navy. It would probably resemble a flatter shape like the T-50, only optimized for ground attack. Perhaps a J-31 like aircraft done in traditional MiG style.

Since they all get munitions from the same sources, the bigger question is why they are not used by the various aforementioned aircraft. Scalp and Storm Shadow are similar, yet incompatible. Typhoon cannot use MICA, although its been tested on Gripen. None of the Eurocanards use Brimstone even though it has obvious value well into the future. AMX, Jaguar, and Tornado – international designs – suffer the same. It’s almost like NATO members are growing further apart as they cooperate.

TVC is unnecessary. Its already adjusting control surfaces at 180 correction per second.

I like the F-35C best, but all of them seem to be missing something.

The F-35A needs color to it. Maybe a thrust vectoring flat nozzle. Wingtip pods with rails would look good on the F-35A, too.
The F-35B needs a gun. The Marines need a gun on their aircraft. The X-32’s front intake looked like something a Marine would love. The F-35B should be uglier.
The F-35C needs twin engines. It needs a subvariant with swing wings.
All versions need all-moving rudders.

Let’s not forget that MiG-25 existed in the era of ground controlled intercepts using the pilot as the weapons officer and people on the ground steering his aircraft like one would steer a missile towards its target. AA-6 was built with technology closely related to SAMs, by the same design houses. AA-6 is simply a giant missile for an AAM, but relatively modest for SAMs of the era. It was always suspected that the AA-6 was perfectly capable of command guidance with terminal illumination from a ground-based source once released by the launching platform. Hence it’s short published range was always done with a cough and bull statement. Ballistic trajectories were always used with SAMs of the era and a loft over the high altitude target was considered more optimal than an attack from underneath. Slide rulers and plotting boards worked wonders.