Should I apply to roles in cities I'm not willing to relocate to, just for interview practice?

Use caution. If you know you won't relocate, don't apply to roles where relocation is required — the first question a recruiter will ask is whether you'll move, and as soon as you say no, the conversation is over. You risk burning a bridge with a company you might want to pursue later. For practice, focus on roles where you're a genuine candidate. Local or remote-eligible roles give you real practice without the dead end.