The solution to S-300/S-400 is simple - saturation attacks using low cost, high altitude cruise missiles. Fly them too high to be intercepted by AA guns, with a payload too large/powerful to ignore, and the S-300/S-400 would be forced to expend a hugely expensive missile to intercept. Continue sending the wave until all missile are expended, then let your planes attack.
The biggest problem is likely to find a military contractor willing to build an inexpensive high flying drone.
These missiles mimic the radar signature of a full sized plane. They’re extremely expensive, but can absolutely be used to force the SAMs to expend their missiles.
I’m thinking of something a few orders of magnitude cheaper. Flight need not cost millions. Airfoils used for human powered flight produce planes weighing 300lbs, powered with only 300 watts. Scale this up to a 3000lbs flying bomb, using 3kw, or less than 5HP. Let it slog along at 40km/h, and in an 8 hour transit, they’ve covered over 300km. If electric, that requires just 24kwh of batteries, contained in 5 Tesla battery modules at 55lbs each, for 275lbs of batteries. Each module is around $1500 used, so $7500 in batteries. Foam and plastic wrapped wings with aluminum spars could be constructed for a few thousand dollars at scale. Add in the Mark 84 payload at $3k, and a navigation system for <$1000. Total could be well under $20k. Launched in a wave of 1000, flying at night, tens of meters off the ground to avoid radar, rising to maximum altitude prior to getting within AA range, roughly an hour before destination, this $20M swarm of 1000 2000lbs bombs needs to be neutralized by the enemy. They can only use their S-300/S-400s. Each cruise missile would be capable of taking out any ship in the Russian Black Sea fleet. Sevestapol would be a indefensible against nightly attacks launched from just 300km away in Odessa. Even Russia would eventually run out of S-300 missiles. Probably in the first night. Target the launch points? Where? Anywhere within a 300km radius? The day before, drones could fly themselves (unarmed) to 100 different preset locations within this 300km radius, met by small teams with generators to recharge the batteries. 100 teams, each charging 10 drones. Would be hard to locate and destroy the launch points.
The ADM-141 TALD is designed to be much cheaper than a HARM. It alone can't destroy the SAM, but it can distract it. I guess if you use enough of them you could call it saturation.
Just needs to be optimized to get above anti-aircraft range, and with a sufficient range. Mount a large enough bomb along with sufficient gps guidance and terminal optical guidance (make it a threat they can’t ignore) and they’ll have to shoot it down.
HARM is more of a defensive missile at this point. The strategy revolves around SDB and JSOW saturation attacks. Both are mildly stealthy weapons with long ranges, relatively low cost and aircraft can carry large numbers of them, particularly the SDB
The biggest problem is likely to find a military contractor willing to build an inexpensive high flying drone.