True, but just because the Russian's can't afford to build bigger ships atm ss means that their current ships are not worth looking.
It is not too hard to imagine a hypothetical war on China's periphery, unthinkable yes but not impossible with all the current tensions going on. In those scenarios, a upgraded Type 56a can do more than just being a patrol vessel, such as a mobile land strike platform, freeing up larger vessels for more pressing matters. It would be a monumental task for an enemy force seeking to destroy such vessels hiding in China's shore line lobbing cruise and anti ship missiles.
Russian ships are compromises, reflecting a desire to have a lot of firepower but also the constraints of Russian industry. You think the Russian corvettes are great ships but there's a reason why no other maritime heavyweight (except Israel) bothered to pack that amount of firepower into ships of that displacement. That many weapon systems require a crew of a certain size of operate effectively and that crew needs proper rotation, rest, and nutritional intake, all of which requires ample volume dedicated to crew quarters, food storage, and food preparation. Somewhere along the line, the Russians and Israelis said "screw it" and shoved a bunch of firepower into a tiny hull with limited consideration for logistical factors which NATO and Chinese naval architects found unacceptable.
Your claims of the 056s' inadequacies cannot be rectified by simply up-arming as the facilities inherent to the design can only support the weapons systems they currently have. The 056A can support a certain crew size, which can effectively man their existing systems and no more. To shove additional systems in the vessel means to take away manning from other systems leading to an overall degradation of capability and readiness. We only have to look at the USN 7th Fleet to understand the consequences of crews that are fatigued by too many tasks and suffer from insufficient rest.
Simply put, your interpretation of Russian ships is flawed. The fact that their vessels displace so little while packing a large punch is not a good thing. It means they wanted to build larger ships but couldn't, so they had to compromise and shove it in a smaller hull resulting in reduced effectiveness. E.g. their Gorshkovs are supposed to be destroyers but due to various constraints, they ended up with a 4,000t design trying to do the job of an 8,000t ship.
What a ship can or cannot do does not necessary depends on its weight and class. And perhaps the most dangerous thing to assume is that one has enough of a certain class of ships for a particular job. One must remember that the Type 54A frigate still uses a older model radar that while is still capable is really starting to show its age, whilst there is currently only a handful of the current destroyers are capable of area fleet defense. And even fewer of them are capable of land strike missions, and certainly none of the current frigates can do so as well. In the event of a war (especially one that occurs near China's borders), the majority of the principal surface combatants will be expected to conduct defensive fleet air defense for the carriers and the like, leaving precious few vessels in the strike configuration.
Even if the Type 56a is not called upon to conduct cruise missile strikes, it can most certainly be expected to conduct day-to-day littoral patrols and showing the flag ops due to their cheap operating costs, which in light of ever more capable submarines and the propagation of cheap UAVs means that at the very least the Type 56a needs an upgrade to its sensors and self-defense weapons to remain relevant.
Plus a U VLS will greatly enhance the Type 56a's capability for ASW warfare as well with ASROC missiles.
China will not commission anything like the Buyan-M because China has something called an air force. Two, in fact, one PLAAF and the other PLANAF. If you have missile-carrying aircraft, you don't need missile-carrying boats. That's a principle exemplified by the Type 22 FACs whose utility faded over the years as the PLANAF built up its strength. If China needed to conduct strike missions, the JH-7s, Su-30s, and H-6s are much better options than a Sino-Buyan.
The 056s' role is simply to be tripwires during peacetime and fleet escorts during wartime. The sorts of missions you have in mind for it are unsuited to a vessel with 1,400t displacement. You should instead wish for accelerated J-16 and H-6K adoption by the PLANAF which will allow them to conduct strike missions much more effectively than building a dedicated missile boat like you want the 056 to become.
The 056 also already possess ASROC capability with the slant launchers, there's no need to add UVLS, not that it will fit anyway.