Old hand at blueberry wine. My favorite. Don't add any more sugar if you started at 1.080. Blueberry ideally starts at 1.085, so you are very very close.
I suggest you let it ferment to 1.030 or so, and transfer to a clean carboy. It will still be pretty active then, so use a 3-piece airlock and allow enough headspace so you don't overflow. Save any leftovers in an appropriately sized jar or bottle in the fridge, where it will clarify and can be used for topping off or sipping.
The wine will undergo an anaerobic fermentation phase in secondary.
When it ferments dry, you should rack to a new carboy (there will be a lot of lees) and use k meta and potassium sorbate to stabilize and make any sugar amendments after at least 5 days have passed from the stabilization. It is good to amend blueberry on the back end with sugar; it really brings out the blueberry flavor.
How much? I filled a flask and then added sugar until I got the taste I wanted, then put a hydrometer in to read SG for future reference. Hit that SG by adding sugar to the remaining batch, then pour your test sample back in.
Do let the blueberry sit in the carboy and settle, and initially rack it about every month, or when an inch or more of lees accumulates. It will shed a lot of lees and debris over time. After at least 3 months - and up to 6 months - of settling and racking, you can rack one last time to a clean carboy, add k meta and bottle.
It is best after at least a year has passed from primary. You will be rewarded with a beautiful smooth wine for your patience.