No, if you don’t have two trusted devices you can register another trusted phone number. Like that of your Partner. Your mom. Your landline.
If you bring your iPhone as your only trusted device and use also use that iPhone number as the only way to access this trusted device, you aren’t asking for trouble, but you’ll get it. Like locking all your spare keys in your house and then then expect to be able to get them when you lose your key.
I know that google has recovery codes you could theoretically bring with you on a piece of paper, but no, thank you. Such information belongs in a safe, either a physical one or at least heavily encrypted. But if you go to that trouble, you might as well register secondary phone numbers.
