sidecar lags, freezes, and is unstable for macbook (2017) with 2.4G WIFI connected

Just finished Apple support call. They had me turn handoff off and on several times on both the Mac and iPad. I reset my permissions (FINDER—>File—>Get Info—>sharing & permissions—>action button(gear)—>apply to enclosed items...—>ok—>restarted Mac). And a quick terminal command. Type everything within the double quotes: “diskutil resetUserPermissions / ‘id -u’ “ (no space after the last single quote). If it doesn’t work in the terminal try replacing the single quotes with semicolons or asterisks in place of the single quote. Then restart Mac. Try connecting again. Hope this helps. Seems to have solved my issue.

My case is exactly the same but with my IMAC 5K 27 inches and my IPAD PRO 3th generation. What can I do to fix it? It used to worked fine before the last upgrade.

Same problem here, but even when I connect with cable the feature is unstable. Ipad screen freezes and I need to disconnect sidecar. I'm using a MacBook Pro 13" 2019 and iPad Pro 12,9" 2nd generation.

Same issue here. 2016 MacBook Pro 13” with a iPad Pro 12.9” (3rd Gen). Mouse shows considerable lag and then the iPad display (using sidecar) freezes, requiring me to exit sidecar completely to gain any functionality back. I’m using Duet display instead right now, without ANY issues. On the phone with support now. Will update if anything comes of it.