Just a note if you are thinking about using Fiasp: it is quirky and takes some time to get used to.
I have been using it for a few years now and love it once I got used to its quirks. The main one is, for me, the speed it works is highly dependent upon my BG.
If my BG is in double figures, it can feel as if I am bolusing water until suddenly after more than an hour, my BG will plummet. So it is doubly important not to rage bolus.
On the other hand, if my BG is in the 4s, it will start working immediately - faster than I digest the food. So, I have to bolus after eating when my BG is at this level.
But, when my BG is in "normal" range (between about 5.5 and 8.5), I can bolus just before eating.