Which version of what exactly? Certbot is at 2.11.0 currently.
If you're having problems with NPM specifically, please refer to a NPM support channel. The volunteers here don't have much (or any for that matter I believe) experience with NPM and it's usually hard to debug. Although it's great you've managed to get and post the Certbot log.
Speaking about the log:
This error seems to be coming from the following piece of code in the certbot-dns-ionos plugin:
(Please note that the certbot-dns-ionos plugin is a third party plugin and is NOT maintained by the Certbot team.)
That part of the code is only run when the response of the IONOS API is NOT a HTTP 200, so the IONOS API returned a different status code.
Unfortunately the plugin seems to be written rather poorly to handle this specific problem. I have no clue what the actual contents of the API response was. The plugin just makes some assumptions.
There is an issue (Exception while handling ionos API error · Issue #24 · helgeerbe/certbot-dns-ionos · GitHub) in the plugins repo that mentions this problem just exactly. And that issue suggests one of the possible reasons hitting this key error is if the API returns a "missing or invalid API key" error.
Are you absolutely sure you have set up your IONOS account and NPM correctly for API access?