Insurance co.s look at cases and risk assess; after all that is what insurance co.s do - balance between risk and safety.
Re your existent condition if it still is a condition, even though as you say you've "been stable" they will still regard it as a "condition" for insurance purposes.
Someone else mentioned annual cover. I've used annual multi-trip for years but you must, and i stress must, inform the co if there are any changes to your health during that 12-month period or suddenly you begin treatment for a medical condition after you've purchased an annual policy. Dont assume an annual policy covers you, in full, for a whole year.
Travel insurance policies linked to bank accounts (freebie policy with some current accounts) are often basic policies; read the small print. Does it cover for trips outside of Europe, for example.
And on another point, some policies now exclude countries you might think are automatically included. Mexico is a classic example; a popular UK visitor haunt esp for All Incl. But some co.s are NOT covering for Mexico. And here's a surprise one in "no longer covered"........
The Canary Islands.
No joke. Some travel ins co.s wont cover for The Canaries because docs on some of the islands send sick tourists to private hospitals on the islands.