Nobody is protecting digital children and it’s almost always disingenuous when this argument is claimed to be made. The effort is to stop the normalization of the sexualization children. Lolicon is exclusively about romancing or sexualizing children. Deluded adults who think what happens in lolicon material is ok are potential risks to real children. Allowing such a risk to children for the pleasure of these adult is absurd.
Use an Instagram-specific site container to isolate your activity from your normal browsing. Imo this is really the only thing that matters that doesn’t have to do with your self control. You want to make sure Meta gets nothing from cross-site tracking and containerizing IG should do that. Also, don’t visit links to and from IG. Look it up manually through IG search.