Should China prioritize Indonesia and Malaysia over others in the region? Of course. They are much bigger fish and are not being offered stealth aircraft by anyone else. China can also offer to build up local EV and renewable industries for greater influence. With Australia looking to turn itself into regional superpower, Indonesia should feel very threatened. It is the biggest catch in the region. Again, China will have a lot of weapons it can offer to Indonesia by the end of this decade. As Indonesia grows, it should no longer have to bow down to Western countries due to military weakness.
Indonesia has a bit of a complicated history with China. I doubt Indonesia will ever be much closer to China than they are to the US, which isn't very close. As the 5th most populous nation on earth despite their economic issues they have the weight to stay principally non aligned. In the last 20 years they have bought fighter aircraft from both Russia and the USA and are a stake holder in South Koreas Stealth program
China would have to back off from the southern end of the SCS which includes some of Indonesia's economic zone
China/Indonesia back ground
China supposedly was in the process of shipping weapons to the Indonesian Communist party just prior to 1965 coup that disposed Sukarno, this was one of the main reasons given for the coup. Chinese Indonesians were among those targeted in the massacres that followed.
Every so often Indonesians run amok and take out their economic frustrations on Chinese Indonesians, most recently in the late nineties. Chinese Indonesians tend to preserve capital across generations more so than any of the indigenous groups, this has lead to Chinese Indonesians being over represented in the rich list.