Leaving aside the inherent imprecision in using keel-laying dates as proxy for radar system...
German F125 predates 055 and its TRS-4D radar is said to be a GaN-based.
Japanese 25DD is roughly contemporaneous with 055 and its FCS-3A radar is said to be GaN-based.
Why is it implausible that China could likewise put a GaN-based radar into service in a similar timeframe?