I want to speedrun Odyssey but capture cards are too much, any help?

Point a camera/phone at it and record it, Speedruns don't need to be high quality, they need to be fast. Actually, you don't even need video proof as long as you don't get a Top 50 time (this changes depending on the game your speedrunning).

If you want high quality videos, you either need to emulate the game (only works on older consoles tho') or buy a Capture Card.