Comment by elahd

Keys on shabbat is doable without an eruv¹²³. (It's not considered carrying if it's an integral part of your clothing.) Eruvs are more for strollers/carrying small kids, dessert/wine when invited for lunch, etc.

¹https://thekeybelt.com

²https://www.judaica-world.com/index.php/adjustable-shabbos-k...

³https://maps.app.goo.gl/ptpGhwLeckdUTjUd7