I haven't tried carb blockers, but I'd encourage you to read about retrograde resistant starch. If you are going to eat a starchy food (potatoes, pasta, rice, even bread, etc), it turns out that making that dish ahead of time, cooling it in the fridge (or freezer), then reheating it converts a significant percentage of the starch into a type of resistant starch (this type is retrograde resistant starch, RS3 -- there are 4 types). You cannot digest resistant starch, but it is manna for your gut bacteria, and worth eating even for just that reason. Repeated cycles of cooling and heating will convert a little more of the starch, but by far the biggest bang for the buck is the first cycle.
Some people mistakenly believe that you need to eat the starch dish cold (e.g. cold potato salad), but that does not matter as long as it has been cooled.
I would be really surprised if you could buy a carb blocker that would be as effective as this simple trick, and it promotes a healthy gut biome for you to boot!
Here's a link about it:
https://freetheanimal.com/2014/10/re...esistance.html