With respect, I think that taking lessons in naval warfare from ground warfare is a bit questionable.
Due to the ranges involved naval warfare, drones of sufficient range and power and communications capability are already going to be much larger and more expensive than your average ground combat drone. Not only that, but they have to carry much larger payloads to reliably take out a ship, and they have to be fast and evasive enough to be reasonably capable of penetrating the layered defences of a naval battlegroup when massed. Not only that, but naval drones have to be navalized (made resistant to salt water spray, collapsible wings for storage, etc) and launch platforms are expensive ships, not cheap patches of dirt.
None of the above are problems for ground combat, which makes ground combat suicide drones much cheaper to produce and field in numbers. If you look at current prototypes for naval strike drones, they mostly look like slightly smaller jet fighters instead of much smaller ground combat drones.
Well like you say, we don’t have any insight into the PLAN planning or R&D projects. From the information we do have, the Type 055 Destroyer has an integrated power system that some articles have mooted to be laying the groundwork for a future railgun system. It’s possible that the PLAN has also made some sort of breakthrough (or is close to doing so) with the power miniaturization or storage systems that would be necessary to fit one onto a Type 055. Either that, or the PLAN is doing this as a vanity project, which is pretty out of character for them.
As for hypersonics, naval missiles are housed in VLS silos that can’t be reloaded at sea. Even if the mooted railgun can only fire a few dozen or so shots before requiring a barrel replacement, that still works out favorably if the barrel replacement can be done at sea. Also consider that it’s possible that hypersonic missiles might still be impacted by jamming or some future interception system, whereas a metal slug travelling a mach 3 tends to not care about either. As for a sub surface nuke, setting aside the very obvious environmental damage (China plans to fight near it’s home waters so can’t be so blase about nuclear contamination), using any sort of nuclear weapon is a huge step up the escalation ladder and would be only one step down from striking a US base with nukes.
