In Mojave, when I use the Services menu to print a selection, I get a message that the Services app is not optimized for Mojave and will not work in newer OS's. I don't know where that app is located and I assume that it's by Apple. I find it strange that Apple would not upgrade it to 64-bit, even if it works in Mojave. Do you find anything similar in Santa Catalina?
Strange, but I just used the Services menu to print a selection and no optimization message popped up. Tried it in Safari 12.1.2 with macOS 10.14.6.