Stacy, Let me start with I truly think that you are feeling overwhelmed and for that ((hugs)).
I think that you may benefit from (re)reading
The Basics: New to the Group? Start here! and the explanation of Typical Lantus cycle.
The following is
not a criticism by any means, it's merely
my opinion based on reading your condos and Ivy’s SS and in response to what I know is your willingness to learn more.
You say that Ivy has “deep dives”. I
do not see this. I
do see fluctuations in BGs. We want that! We want to see the insulin take the cat into blues and greens.
Meter readings have a variance of 20-25% including the Libre 3 (see the last couple of pages of the manual, screenshot below)
What I have personally seen in my cat and my understanding:
DIVE - the difference in BG readings greater than approx 40-45% and an hour apart from one another.
ACTIVE CYCLE - for an active cycle I personally consider it something like 25-30% by +2/+3 (- so about 5-10% beyond meter variance).
Now looking at your SS-
8/21 AM (cycle 1 dose increase) - All these readings are within meter variance, no diving, no bouncing, just fluctuations within meter variance.
8/21 PM (cycle 2 dose increase) - PMPS 400 and stayed high for hours - Bouncing
8/22 AM (cycle 3 dose increase) AMPS 353 +2 189 [46% DIVE and early in the cycle, feed higher carbs] +3-+9 GREAT JOB!!! at keeping her surfing

. I personally would have fed LC at/after +5. Feeding later in the cycle can shorten the duration of the insulin.
8/22 PM (You shot a reduced dose) PMPS 241 - Bounce. I would have shot the full dose.
8/23 AMPS 374 +2.75 247 (34% ACTIVE CYCLE) AM+10-PMPS: you said that ‘Ivy’s diving and fast’. I see that she was flat and coasting. Even with the AM+11.25 green 88 BG, I still consider Ivy flat and coasting. That 88BG is 26% of the 122BG reading (within meter variance).
8/23 PM (You shot a reduced dose) PMPS 122 +1 207 Food bump (you may want to examine what you fed at PMPS because that is a big food bump) +2 155 higher than PMPS but within meter variance, by PM+5 all the carbs you fed shortened the duration and any action of the insulin and she climbed through the end of the cycle into the reds.
8/24 AMPS 389 Bouncing- take the cycle off from FD
8/24 PMPS 327 +2 221 (32% ACTIVE CYCLE)
8/25 AMPS 194 Bouncing - take the cycle off from FD
I feel that you are confusing
Diving with
Active Cycles. In the last 10 cycles, there was only 1 instance of a dive.
You are correct that Ivy clears bounces quickly. That is fantastic (and personally wish my Cleo wouldn't take the full 6 cycles to clear a bounce

).
I also feel that you are overusing 15% Carbs. It should be saved for Dives, Low BGs, and/or right before Onset if for personal reasons you need to abort they cycle.
I want to reiterate that I think you are feeling overwhelmed as we all have felt and that you are doing a good job.
This is just my two cents for what its worth.