JARI USV is only ~20 tons. It can even fit on a flatbed trailer.
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The JARI USV is perfectly capable of patrolling contested waters and disputed islets & islands in the SCS and the ECS, plus acting as expendable scouting and air-&-sea early-warning units. Needless to say, though, any USVs of that size is absolutely incapable of meeting the requirements for convoy escort and ASW missions in the "true blue" WestPac, alongside CentPac and the Indian Oceans.
To build what would be minimally/optionally-manned 21st-century counterparts to the destroyer escorts (DDE) of WW2 and the Cold War, China would require ships that are in the low-thousands of tons of displacement range (2000-3000 tons).
Simply put, 053H3-sized or 054-sized warships with substantial short-range (5-5-5 quad-packed SAM) and point-blank (HHQ-10 and/or H/PJ-12) air defense capabilities, substantial ASW capability, alongside minimal/negligible anti-ship (YJ-83) capability, plus 3000-4000 nautical miles of endurance.
Whether said warships are normally, minimally or optionally manned doesn't really matter much in this case.