You can bring your history with you. Export it, map your columns once, and every day you logged comes across dated as the day you logged it. It is free and takes about a minute.
It is yours, it does exactly what you told it to, and nobody is going to sunset it or start charging for it.
A spreadsheet cannot remind you, and it will not tell you anything you did not already work out yourself. Most people also describe the upkeep as a second job: the notes column is the first thing to go.
Export menus move around. If these steps do not match what you see, look for anything that says export, backup or download, and pick the CSV.
Whatever you tell it to. The importer reads your headers, guesses what each column is, and shows you every guess to correct before anything is saved. Your own words for done, whether that is an x, a tick, a 1 or the word yes, are all recognised.
Formulas, charts and conditional formatting. Those were doing the analysis job, and the point of moving is that you stop maintaining them.
The export sits next to the import, on the same free plan. Everything you log comes back out as a CSV whenever you want it, including your medication history. That is the whole reason this page can exist: nobody should be stuck somewhere because their record is.