Oh, I’d only do that if the players are similarly powergaming. If they’re not it’s unfair, if they are the base game balance becomes koring. The challenge should scale to the party!

Pretty much how I DM.

Bosses have prep time. Glyph of warding can be cast on a page in a book, with trigger conditions specified by the caster. E.g. when a good-aligned creature with ≥8 int comes within 10ft of it.

Explosive runes are 5d8 damage (dex save for half) per glyph.

Nothing says it can’t be cast on more than one page.

A 50 page book with a glyph on every page means 100 dex saves for 5d8 each. Evasion is nice but you’ll fail a save eventually.

Your “friendly” neighborhood lich has had time to prepare dozens of these. That tempting library full of magical books might just be a TPK.

As a “consolation prize” at least the player gets to roll 100 d20s at once! Multiple times if they survive the first book.

The players know that. Their characters don’t.

Note that PGP only encrypts the body, not the subject, sender, or recipient. So it’s only partial encryption and not very private compared to modern messaging services like Matrix. This is a fundamental limitation of email. It’s “Pretty Good Privacy”, not “Very Good Privacy”.

No. Proton only encrypts message content to/from other Protonmail users. Message subject, sender, and recipient aren’t encryptable for email.

I’ll second Fastmail.