AFAIK, both US and Russia load their ICBM separately, at least set warhead+bus and missile boosters apart. Especially larger ICBM is normally loaded separately between stages, Peacekeeper was loaded in several parts by a much smaller vehicle than the one in satellite image.
I will attach video and picture later in this post. Because it is weird that the suspected vehicle looks like a compact TEL instead of a semi-trailer trucker that US and Russia use to transport their ICBM. It is not like China doesn't have similar thing in inventory, for instance, Tianzhou was also transported in containers by semi-trailer truck.
First of all it is unlikely to be civilian given the camo it has and secondly it is not necessary to transport or erect a large solid ICBM in its whole and it is usually done by different vehicle in practice.
Peacekeeper ICBM emplacement:
Russian story is also similar, the warhead + bus was installed by much smaller vehicle.
View attachment 111093
ICBM transporter:
View attachment 111095
Chinese erector for ZK-1A:
View attachment 111098
Animation on how Chinese heavy solid rocket transports and erects: