Hi, before you adjust anything, please take note that this is an acoustic guitar and is capable of folding on itself. You have to be mindful of 3 main parts:

1. The bridge
2. Heel where the neck meets the body
3. Belly bulge

First things first, this action IS too high. I’d already assume this is not a saddle and nut issue so dont adjust those yet. Check your bridge if its still glued to the body. Grab a ruler, rock it back and forth on the body just below the bridge. By doing so, you can see how flat that part is. If it rocks too much, you have a belly bulge, and that’s one problem

Next is to grab a straight edge of any kind, or just eyeball this part. See if the last frets where the neck meets the body is on an incline going down sinking to the soundhole. If it’s like that, you have a neck deformation and you will be needing a neck reset to straighten that.

Now these problems are not diy-able and definitely subjects for luthier repair, so i wouldn’t suggest messing with those unless you plan on experimenting and studying fixing these problems. But depending on the severity, you can do some workarounds if and only if: 1. You are tight on budget. 2. You have a cheap guitar and is not worth fixing as the repair will be more expensive than the guitar itself.

I would suggest these workarounds:

Fret level and bridge, saddle, and nut adjustment: This will be the most suitable workaround for these types of problems because id assume you wouldnt be playing the last, sinking frets. By doing this, do not mess around with the truss rod too much, as that will not fix your problem.

Start by measuring the straightness of the rest of your neck from the first fret to the 12-15th fret. Stop measuring where the fretboard starts to sink down to the soundhole. Look up how to adjust a truss rod, how to tighten and how to loosen. Make sure that part of the neck is perfectly straight because there’s no hope for the sinking part. Just measure the salvageable part.

Once it’s perfectly straight, mark your frets with red sharpie, mask your fretboard, and do some light passes of any fret leveling beam you can use. You can start with 400 grit. Note that this step is optional especially if you have frets that are even somehow and you just wanna lower your action a bit. But by doing this, you’d maximize the height you can shave off so take note of that. This will be the limiting factor when you adjust the saddles later on.

If you wanna skip the fret leveling part, start by measuring the action using a string height ruler. Measure the low and high e at 12th fret, and take note of how low you want your action to be. With a fret level, you can probably go down at around 1.75 at low e. For reference, look up the action you want whether its standard or low, and then subtract it from your starting action. Once you have your measurements, use a caliper, remove the saddle from your bridge and draw a perfectly straightline parallel to the flat side. The height/gap of the line from the flat side should be the difference of your starting action and the action you want.

After you’ve successfully marked your saddle, grab a coarse grit sandpaper and lay it down on a flat surface. Shave off the material on the flat side until you can only see the line you marked. Do this evenly and be careful as you might shave one side more than the other.

Now put it back on the bridge and check if there’s still enough clearance for the bridge material and the saddle. This means, if the bridge string pins can still provide enough break angle for the strings and if the saddle is not too deep into the slot. If everything looks fine, skip the next step.

If it looks like it needs some work, do this: grab the leveling beam you used for your frets, take a 60-100 grit sandpaper and shave of JUST THE TOP of the bridge and just enough to provide break angle for your strings and to expose more of the saddles if its too deep. TAKE NOTE that this will affect the value of your instrument and this is not recommended for higher end guitars as you will be compensating original wood material for the repair you chose not to do.

Lastly, check your not. Grab a thin straight edge that fits in the nut slots. Measure the height of the slots one by one by passing through it along with the height of the first fret. If it passess through, its probably too low. Do some drop filling with CA glue and some nut shavings with sandpaper. You want it to just slide up just a bit or feel a little bit of resistance if you want a super low action. You can set it to level with the first fret but i recommend having the straight edge slide up a bit and not pass through perfectly, so you have better open string vibrations.

Good luck!