I'd suggest going to high bpm maps which are 6-7 stars considering your level, then, use Halftime (May result as ht depending on your skin) on the said maps. Thus will result in you getting able to practice on new patterns with manageable bpm as well as less accuracy required. However, do NOT just play halftime, i have done that before and in result whenever i tried to play higher bpm than usual or anything without the mod, I would get extremely low accuracy, so balance the use of it.
Eventually, while practicing both no mod (along with other mod obliviously if you use them) and halftime, You will pass up to 6 stars level, If you still can't do them after practicing, start with some easy 6 stars such as Period and move up gradually. You can also attempt to halftime 8 stars for a harder challenge if you feel bored while practicing out.
In case you feel like your bpm reading skill lowered too much by using halftime, use doubltime on 2-3 stars maps for the day in order to manually regain some bpm (It worked for me, at least).
Additional note: If you feel like the song is already slow enough at 6+ star level, try using Easy (May result as Ez depending on your skin) instead.