Certainly is a problem for me and I've seen others say the same. Every doctor I've been to has mentioned it as an issue.
"Caffeine — a major component of many varieties of coffee and tea — has been identified as a possible trigger for heartburn in some people. Caffeine may trigger GERD symptoms because it can relax the lower esophageal sphincter (LES)."
I get really bad GERD from coffee and black tea, a bit less from green tea.
I don't get GERD from Mate tea or energy drinks. So I think it's not the caffeine. Since they both contain high amounts of caffeine, even higher than black tea.
I've noticed that if I eat more fiber I can somewhat mitigate this. But it needs to be consistent. Not just a little extra fiber before coffee.
BTW a high-fiber diet can be a natural ozempic by raising GLP-1 levels.
[1]: https://journals.lww.com/tcmj/_layouts/15/oaks.journals/down...