The point at which a breast is too ptotic (saggy) to augment with an implant in my opinion and experience is when the nipple is lower than 2 cm below the level of the inframammary crease behind it. If the nipple is at or above this level then an augmentation with an implant can be done with a minimal inframammary crease scar and the breast will get a lift "effect" although not a true lift.
Also if the nipple level is at or above the 2 cm below level then a mastopexy (lift) will not make much improvement and is probably not worth the scars and does not do what the patient is usually looking for.
Combining augmentation and lifts is doing two different operations on the same breast at the same time and they tend to work against each other. The degree of complexity goes up, predictability of outcome goes down, and the need for revisions goes up.
In general, a true lift needs a "lollipop" type incisional scar but some borderline situations can be handled with a periareolar incision alone and yours may be one of them. "Crescent" mastopexies are to be condemned as misconceived. I also disagree that the the size or weight of implants alone causes bottoming out.
Assuming an exam confirms the nipple level isn't too low, I would recommend an augmentation alone with a low profile implant that fits the width of your breast and will fill in the upper pole. This should give the effect of a lift and an increase of about a cup size. If you still feel you need a lift later then consider a periareolar lift but not at the same time as the augmentation.
Both of these procedures can be done under local anesthesia with IV sedation in an office setting that is properly experienced and accredited.