Once they start weaponising T-bills, no country will touch them. The financial consequences will be worse than loosing the domination of the dollars.
Its quite clear by now that there are powerful elements within the US ruling elite that are desperate to push China to war soon, before they loose their perceived existing conventional military edge.
The worry and risk for China to support Russia too overtly in Ukraine is that these elements in the US would then be able to use that involvement as leverage to push its agents and useful idiots in the EU to apply the same sanction regime that they applied on Russia against China - freezing and ultimately seizing state assets being the big one, but also effectively a trade embargo.
If that were to happen, it is basically trying to force China’s hand in terms of launching AR, because the economic costs would be equivalent to what China can expect to endure should or kick off AR, so there really isn’t much downsides left for China to just get on with AR.
China will not allow anyone else to dictate its timetable for AR, which is why it has thus far resisted direct military sales to aid Russia. But at the same time, China has been unusually explicit in its diplomatic support for Russia.
There is a very good chance that overt Chinese military assistance to Russia for Ukraine would be a prelude to actual AR, if not come after the start of AR to avoid tipping their hand in terms of their readiness and intentions for AR.
