Are you too late to switch to paying Adobe, annually rather than monthly, which will keep the cost at the old rate?
There have been several posts on here about people doing this.
I don't know anything about Luminar, but both Topaz Photo and ON1 Denoise have plugins for C1, which is useful. DXO Pure Raw is probably the *best* of the three, but it doesn't have a plugin for C1.
If you use C1 sessions, this doesn't matter because the session automatically updates, but with a C1 catalogue, you need to manually sync the catalogue after DXO has created the DNG.
*best* ?
My tests comparing Adobe denoise, Topaz, DXO and ON1 show that the "best" varies depending on the individual file being tested, and there is no clear winner, but if I could only have one program, it would be DXO. On1 Denoise was my least favourite. Adobe, was "solid" but couldn't match DXO for detail. Topaz was the most unpredictable, but still capable of giving the best results on some files.
Having said that, the most recent release of Topaz, "seems" to give me better results, than DXO or Adobe (I don't have the most recent version of ON1 Denoise to compare, and I have made no detailed comparisons with this new version of Topaz). But the new Topaz subscription is more than the cost of your Adobe updated price.
For medium ISOs (up to about 5000ISO), most of the time, I still prefer the results from C1, which seems to give good results as long as I use it with selective masking (for detailed subject areas and shadows).