No worries here.
First, I am glad to hear that it is your quarantine tank and I am grateful for the photos so that I could confirm that it was Ich you were facing. That said, I cannot see any information about tank parameters or the salinity/specific gravity. So, if you can check and post those that would be ideal.
In the meantime, I do want to note that at the temperature you have the tank at, Ich has a 5-7 day life cycle. Therefore,it is not unexpected that they are still present at this stage (and it can often look worse before it gets better). Often treatment courses need to run 7-14 days to clear all life stages of the parasite .
Otherwise I do have a few concerns at this point with your set up and treatment plan. First, the medication is reasonable to be using and again the lack of improvement is more likely related to time frame as opposed to treatment failure. That said, you do need to tread with care with that temperature setting because its actually outside the comfortable range for this species. So, if she is looking sluggish, we may need to lower the temperature and accept that we will need to treat for longer to ensure we clear all life stages of the parasite. As well, I can see that you still have gravel in the tank. This should be removed during treatment. This is because the parasite doesn’t spend all its time on the host and will be in that gravel. We always want to be hovering the tank bottom daily when treating for Ich (so we remove as much of the non-host individuals as possible) and that is much easier if the gravel is removed.
So, if you can check those parameters that would be ideal to make sure we don't have that getting her down. As well, they are worth a check since getting the salinity up to ~1.005 would help against Ich too. But also remove that gravel, hoover the bottom of the tank to give the treatment a hand in clearing this infection faster.
All the best,