I have Catalina...I dont know if you actually work for Apple but....do you know is the guitar tuner in GB more accurate now in this updated GB thats in Catalina?I need an accurate free one for intonation setting..

No one at here at MPV works for Apple, we just provide training on their software applications (and many others'). Re the Tuner in GarageBand, I don't know if any changes have been made under the hood to it, but I would suggest that you can't really tune a guitar strictly going by a tuner anyway (software or hardware), you have to combine that with using your ears, using time-honored techniques like beat frequencies, etc.. :-)