The connections are largely standardized. Nevertheless, you still have to be careful. If you choose a designer toilet or something angular or different, then only the corresponding WC seat fits on it. If it then eventually breaks, which happens quite often, you have the problem of finding something suitable. And if yes, then sometimes at exorbitant prices.
If you are unlucky, you will buy a new toilet bowl in a few years because the WC seat is no longer available. So I would always clarify that in advance.
It also depends on how old your current toilet bowl is. If it is still from the 70s or 80s, I would also check whether the dimensions still fit. You have to first clarify which concealed cistern element or which manufacturer you have. Geberit, Grohe, Viega? Just look under the flush plate. There you usually find the manufacturer, model, and year of manufacture, etc.