I need advice!

i bought 3 metasequoia s....it s autumn now but the soil si very bad...so i decided to keep them indoor over winter ....but my question is : it s ok to repotting them now in a good soil mix ? this one is very bad....should i wait till spring? ( and the pot also is very small) they are something like 24 cm height

Do not keep them inside. If the soil is not draining then once the leaves have dropped you could re pot but if it is draining then I would wait until spring, unless you are going into a larger pot and you are not going to disturb the roots, then you could do it now.

Dont worry. Put them outside. If it stays too wet, shelter them. Repot only in emergency.

Isnt metasequoia a swamp plant, or am i confusing trees?

Do you have a picture, there seems to be a couple of metasequoia species? Maybe we can find it.