Any usb-c docking station should work. (should being key, many are lacking something useful - commonly the monitor port is a usb-A video interface with windows-only drivers not a display port that would just work).

Though I suspect a laptop is still what you want. Your phone will generate too much heat to leave in your pocket. Or maybe some backpack (fanny pack?) wearable?

powerbank?

The issue with this is usually that you can't have power from the powerbank going into the only USB-C socket on the phone while the display signal comes out on the same cable. I think it's technically doable, but not usually with dongles that would fit in your pocket.

All the AR glasses vendors have a pocketable dongle for this.

I meant for a pocketable setup as parent explained. You wear the glasses in a coffeeshop connected to your mobile phone (the single USB-C port).

Based on some quick testing this consumes about 1% per minute on my S24 Ultra which makes this scenario unrealistic (at least for me)