The only thing you can do other than getting a phone number to use is try to contact Google, but the probability that you will get a response to overcome this limitation is close to zero.
Below is based on my experience as a Google Product Expert. Note I have not been actively participatingparticipated since several years ago, but I still receive some emails.
You could try using the Google Accounts Community. If your case is found interesting based on the goals that the Community might have, your case might be "accepted". If your post doesn't match one of CommunityCommunity's current goals and it doesn't look like something extraordinary, you might get a canned response, which could be a kindly wording pointing you to a help article.
If your post is found interesting, it might be possible that one of the Google Products Experts will escalate your post to a Google employee, who might escalate the case to a Google engineer. What happens next will depend on the case circumstances.
The top result of my search attempt was: This phone number has already been used too many times for verification bug. It is dated Apr 6, 2023. It has no answer and it's locked. Inactive threads are automatically locked after a few days to avoid infinity chains of "me too" and non-constructive replies.