I also studied it at least two months ago. Let's start with the trills.
I play them poorly, but they are improving; since I am currently obsessed with Bach, I always dedicate a lot of time to perfecting them by doing this: when I get tired of playing a piece/exercise, I smoke a cigarette and start trilling as soon as I feel my arm getting stiff; I stop and resume trilling by rotating the wrist and keeping the fingers almost rigid, and after the arm has loosened up, I resume trilling by articulating the fingers.
For me, it is very necessary to do and redo the first two lines of Partita No. 1 trilling with 2323; I had problems making the 4 heard.
I forgot that I preferred trilling with 23 for both right and left hands, so in Invention 4 *left-hand trill*, I arrive with the 3 on E and start trilling, waiting an eighth note. To arrive with the 3, I begin the preparatory scale with the 3 on A and a thumb passage on C, i.e., C1 D4.
A tip from a budding colleague: the measures from 39 to 43 were difficult for me, so when the theme returned, it was a mental relief; I believe it is the same for you, and therefore when the theme restarts, we tend to play it faster. We must correct this mental bug.
Ps my favorite trillers are Gould, who gives a sense of tension by varying volume and cadence, and Perahia, who is more aristocratic, light, and homogeneous. When I practice trilling, I try to do so by alternating these two ways of interpreting the trill in Bach.
PS 2 A great gem from pianoexpert for trilling with 53 in video tutorial 5
PS 3 if you start practicing trilling, dedicate some trills to it even by pressing a black key; the execution is different and therefore always useful.
PS 4 trills on an octave leap should be played 323232 and not 3232