I am interested in learning more about gematrias. Namely, I am looking for an English-language sefer that discusses some of the more famous gematrias and the lessons that we can learn from them. Like how Amalek and Safek have the same numeric value, and thus we can learn out that modern-day amalek includes our own doubt in matters of emunah, Torah, etc.

Any recommendations are greatly appreciated!

Thanks, YS