Would a second BBL or butt implants get me the best result and do I need a thigh lift?

You are in good company with many others after BBL. Going through round two BBL is likely to only give you more of the same without providing additional shape or fullness, especially in the lower half of the buttock, where the fat tends to survive relatively poor. The only more reliable, predictable and permanent way to achieve your desired outcome is with buttock implants. You may in fact benefit from additional body contouring of your front half by way of a tummy tuck with liposuction of the flanks.  Lastly a posterior thigh lift/lower buttock tuck may or may not benefit the area you describe as “saggy skin right under your butt”. All this can be further evaluated with a virtual consult and eventually confirmed with an in person physical exam. Glad to help.

The BBL results are highly surgeon dependent.  Some board certified surgeons can do almost anything and change the shape of anything.  You have to be creative.  There are some anatomic limits, but, for the most part, dramatic transformations can be achieved. Have the lipo and BBL first; three to six months later, have the TT.

Hello dear,Thanks for the question and photos. Yes, you're a great candidate for TT, Lipo and BBL revision.
In this regard, I recommend you TT, waist and back Liposculpture, getting better curves especially in the waist, improving your body contour.
Finally, I suggested take the fat we get and transfer to the buttocks and hips, to mold them and get better volume, contour and butt projection, is that we know as "Brazilian Butt Lift" (BBL).l recommend you to make an appointment with a board certified plastic surgeon to talk about your goals and anything you need to know.
Good luck :)
Dr. Luis Mejia.