ACA subsidies that were put into place with ACA itself, are still intact. Literally every single continuing resolution that the GOP has put forth does not touch them. What’s going away automatically at the end of the year (again not being touched by funding proposals) is an additional set of subsidies that were added as a COVID emergency measure. The funding resolution doesn’t do anything about those either - they just happen to expire at the end of this year, which is completely expected. After all, they were temporary.

Just to reiterate in case it isn’t clear, one side (Republicans) is not making any changes. The other side is refusing to fund the government in a way that makes no changes. Instead, they’re asking for a change and in an odd way (by extending emergency measures) rather than by passing legislation that, for example, changes how the ACA works.