Look at the article above about the F-16. There are several other sources about this. Regarding the Su-35S, I would like to know where you got that statement from.
It has been known for a long time that the extensive use of RAM materials and new composite materials in the structure of the Su-35S allowed it to greatly reduce its weight and its frontal RCS, so that an estimated RCS index of up to 1m2 was achieved, which puts it on the same level as fighters such as European Deltas or 4th generation North American fighters when treated with RAM. Itae (an institute of the Russian Academy of Sciences in Moscow) has developed materials and techniques that provide a very significant reduction in the RCS of its fighters;
For example, the Mig-29 SMT, which has an estimated frontal RCS of 5m2 (without weapons), has an RCS of 1m2 if treated with Russian RAM material. Itae also managed to reduce the estimated RCS of the Su-35 (6m2) to 1m2 in the frontal quadrant. The engine face was covered with magnetic RAM and the air intake walls also received the same material, which was applied in thin layers between 0.7 and 1.4 mm and applied by digitally controlled spray. Ceramic RAM was applied to the engines and exhausts. The canopy was treated with metallic and anti-reflective material. The antenna was changed position and treated with RAM material, and the radome received selective coating, which changes the conductivity. The difference is that while the Russians work heavily with signature-reducing composite materials, they have not worked as much on RCS reduction as the Americans do. In addition, Europeans also tend to work better with the use of composite materials than with shape techniques. It is no coincidence that there are few stealth aircraft by shape. Furthermore, although the Su-35 is based on the Su-27 platform, they are very different aircraft, since the Su-35 uses several types of composite materials, as well as a large amount of titanium alloys. Even though the Su-35 is capable of carrying more weapons, fuel and equipment, it obviously needs to have its structure reinforced. To make matters worse, the RCS of the Su-27 is estimated at 3-6 m2, depending on the configuration.
In this way, comparing a fighter developed in the 2000s with a fighter designed and developed in the 1970s is the same as wanting to compare a Mirage with a Rafale, but since your intention is to denigrate Russian equipment, without any evidentiary basis, I believe there is no need to dwell on this any longer. After all, what sticks most here are narratives and I am not concerned with that, only with facts.
There is no way a Su-35S would have an RCS comparable to 8-10m2. Generally speaking, 4th generation medium fighters have an RCS between 1-10m2 and heavy fighters between 10-20m2. 4.5 generation fighters have employed a reduction in RCS to some extent. The Typhoon, Rafale, F/A-18E/F and Su-35S programs have sought to reduce their RCS relative to their 4G predecessors: Tornado, Mirage 2000, F/A-18 Hornet and Su-27 respectively. So the Typhoon, Rafale and Super Hornet have reduced their RCS to somewhere between 0.1-1m2, while the Su-35S has somewhere between 1-5m2. Compared to 4th generation models, the 4.5 generation will be detected at a range 25-50% lower. Conventional aircraft of similar geometries and sizes tend to have similar RCS. The F-15 and Su-27 are in the 10-15m² range, the Tornado is likely in that range as well. The initial RCS of the F/A-18A/B is believed to be in the 5-10m² realm, but the F/A-18C/D began incorporating RAM in 1989. The RCS of the F-16A is around ~5m², the C model is slightly stealthier than the F-16A, with an RCS between 1-3m².
In other words, the transfer of 65 F-16A/B MLUs from Denmark, Norway and the Netherlands to Ukraine will still lag behind the RCS of the Su-35S.
The biggest proof that the RCS of a Su-35S is the lack of evidence. I have never read this in any source. It's funny that you are trying to justify yourself here.