That would actually be a nice feature in phone clients. A low-bandwidth mode that lets you select which relays to connect to. Preferably you could also turn off automatic media loading too.

cc: nostr:npub1xtscya34g58tk0z605fvr788k263gsu6cy9x0mhnm87echrgufzsevkk5s nostr:npub16c0nh3dnadzqpm76uctf5hqhe2lny344zsmpm6feee9p5rdxaa9q586nvr