Based on my observation, I would say that the Ream naval base would still be operated, mostly at the very least, by the Royal Cambodian Navy.
Although the possibility of hosting and docking larger PLA Navy vessels in the Ream naval base is still viable, something akin to the Changi Naval Base at the eastern tip of Singapore that does host and dock US Navy vessels.
It is unlikely that the Ream naval base would become a fully-fledged PLAN naval base that is operated by the PLA, however. A classic example would be the Kaneda Air Base on Okinawa that is operated by the USAF.
Is it possible for the Ream Naval Base would be further expanded and upgraded into something bigger and able to host more permanent PLA Navy's presence in the future? I think it is.
Speaking of which, having a naval base close to the proposed Kra Isthmus Canal across southern Thailand can provide a much better safety and security guardian over the canal than those bases in the South China Sea, especially against possible threats coming from a certain country based off the Andaman and Nicobar Islands.
Maybe a Chinese-Thai defense cooperation would be viable next.