When eating low carb, many people need to count fat and protein into calculation. Sometimes referred to as T-A-G (Total available glucose).
https://forum.fudiabetes.org/t/do-you-tag-if-so-how/
Also, with higher starting BG, I usually use a higher CF, and wait to eat until i see bg dropping. With higher bg, there can be insulin resistance, that requires more than a static correction factor. Tandem only has one setting. I use tandem to calc, then add more based on these various factors. Occasionally turn off CIQ, and go back to how I did things before CIQ. Using high temp basals (20-30 min) is another option i use and cancel once heading back down to around 150. Then cancel and turn CIQ back on. This avoids CIQ from counting it as IOB.
My goal is tight control, due to many complications after 55+ years T1D, poor control for first 30. With CGM and pump, have maintained 5.5-6 last 25 years.
But definitely takes more attention and interaction due to limitations of CIQ.