The rewritten TCC (Transparency, Consent, and Control) framework of macOS 26 seems to slow down Apple Event handling a lot in case of apps using the macOS 26 SDK. Some apps experience AppleScript timeouts or failures, others (like DEVONthink) poor performance.
The worst thing about macOS 26 is not Liquid Glass but the overall poor performance and unreliability 
If Apple would at least for one year stop adding features and instead fix the most pressing bugs and bottlenecks.