I don't think there is really a limit to how much garlic you can eat, except for your personal limit due to its strong taste. https://www.healthline.com/health/diabetes/garlic-and-diabetes#tips-and-tricks
I have taken a garlic supplement before. I like it because there is no odor that you might deal with when eating actual garlic. This page to this article made me want to try it. https://www.webmd.com/vitamins/ai/ingredientmono-300/garlic I bought a basic supplement on Amazon (there are a gazillion brands). Diabetes is on the list of things it can help (the list is long). That article also discusses side effects. They are intensified if someone attempts to use raw garlic verses supplements, so keep that in mind too. If you have any issue with bleeding, make sure to talk to your doctor as garlic can increase that.