AFAIK certbot isn't actively packaged for x86 any longer (latest release on 14 June 2020), but @certbot-devs may correct me on that.
If I understand the warning message from snap correctly, you should be able to install certbot by combining the --edge and --classic options to the install command.
That said, you might be better off using the pip method of installing certbot, although I'm not sure if the certbot devs agree with me on this one. For that see https://certbot.eff.org/lets-encrypt/pip-apache or https://certbot.eff.org/lets-encrypt/pip-nginx or https://certbot.eff.org/lets-encrypt/pip-other (depending on your webserver and if you want to use a webserver certbot plugin or not..)