Does severe hardship permit breaking the fast in Ramadan and paying expiation, while taking medication that does not affect one's ability to fast?

Intentionally breaking the fast in Ramadan (definition) without a permissible excuse is one of the gravest sins, and severe warnings have been issued against its perpetrator. What you mentioned about the need to drink coffee or sleep is not an excuse. Rather, one must strive against their lower self and be patient, for fasting trains the soul to abandon habits. Whoever breaks their fast without an excuse must repent and make up those days. However, if one is unable to fast due to an illness from which recovery is hoped, they must make up the days when they are able. If their illness is not expected to be cured, they must feed a poor person for each day. If there is a difference in the opinions of doctors, one should follow the most experienced, religious, and pious among them.