Definitely online at the Apple Store.
You can also look at refurbished Macs at the Apple Store online:
https://www.apple.com/shop/refurbished/mac/macbook-pro
Try deleting the audio units cache manually:
https://acusticaudio.freshdesk.com/support/solutions/articles/35000146023-re-setting-the-logic-pro-x-plug-ins-cache-manually