It was an interesting challenge meeting the advice after surgery, though in most cases the adverse effects reduced with time.
Tea was the easiest, the main brands all do decaff versions that pretty much taste like normal. If you normally use leaf tea you will find you can only get decaff as teabags. I used Yorkshire. In practice I fairly soon found I could use regular tea without problems.
Coffee is difficult to find a solution to, at least if you use a cafetiere to make it as we do. Most supermarkets and brands only have one decaff version, and they mostly seem rather tasteless blends. Not sure whether that is a consequence of having the caffeine removed, or simply that they think that it has to be acceptable to those who prefer bland. The best I found was Lavazza, but all though it says it is ground for any type of coffee maker it included some fine particles which escaped through the cafetiere gauze and made the coffee murky. It probably works better with an expresso machine, and that might help with the taste issue too: the only decent decaff coffee I drank came from an Italian cafe (and I have no idea what brand they used, might have been their own).
I found even one cup of non-decaff coffee to provoke leaks for a good year after the operation (I occasionally tried at home, and once had an issue after a coffee out where I suspect the waitress mixed up when delivering the coffees). Eventually though a single coffee a day was well tolerated, and that was fine for me.
Fortunately alcohol was a little easier, it wasn't long before modest drinking caused little problem. An evening glass of wine was welcome after a day having always to be thinking about whether a pad needed changing. Now, several years later, I can drink moderately much as before (say, three glasses of wine) - problems only come on occasions when drinks flow freely and I lose count. There are non-alcoholic versions of some drinks; I didn't come across any acceptable wine in that category and in fact they were all so dreadful I quickly gave up trying different makes.
Beer is another matter, there are some decent tasting substitutes. I recommend those made by Adnams: a decent regular pale ale available from M&S and the widely available "Ghost Ship" which tastes credibly like a strong ale. Some of the continental breweries also do good ones, with Erdinger wheat beer being widely available. At the moment I don't have a strong suggestion for a lager-type beer, M&S used to do an excellent Czech beer (which it said was made by Staropramen) but they have replaced it with another not as good. Unfortunately "real" Staropramen no longer seems available in the UK, the brand has been licensed so rubbish British lager can be sold under its label (just as has happened with beers from Carlsberg, Kronenbourg, Becks and others that remain excellent in their native country).
You may be able to tell that I quite enjoyed doing the research ...