1-2 second lag between walking images or slider reaction

You can try to optimize catalog.

My problem is resolved by optimize catalog.

It's very slow for me too.  Selecting thumbnails doesn't update or takes very long to update.  I can't do any work like this.  This happens after some updates.  Lightroom become less interactive and more slow so that changes don't update quickly.  A few version back it was perfect and I didn't realise how good I had it.  Now it's like working on a computer from 1995.  

In Lrc, click on Help, then System Info, click on Copy. Using Notes (or whatever text editor) past that in, then cull out (copy) just the info from top down to just before plug-ins. Paste that into a reply (please)

Interested in what LrC reports as:

LRC version (just in case)

OS version

RAM

GPU make/model/driver (on a MAC, not much you can do about that, but it might be informative)

for example:

Lightroom Classic version: 12.0 [ 202210031128-9cb7185d ]
License: Creative Cloud
Language setting: en-US
Operating system: Mac OS 12
Version: 12.6.0 [21G115]
Application architecture: x64
Logical processor count: 8
Processor speed: 2.8GHz
SqLite Version: 3.36.0
Built-in memory: 16,384.0 MB
Real memory available to Lightroom: 16,384.0 MB
Real memory used by Lightroom: 1,998.2 MB (12.1%)
Virtual memory used by Lightroom: 37,759.4 MB
Memory cache size: 30.0MB
Internal Camera Raw version: 15.0 [ 1261 ]
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 323MB / 8191MB (3%)
Camera Raw real memory: 327MB / 16384MB (1%)
Standard Preview Size: 2048 pixels
Displays: 1) 3840x2160, 2) 2880x1800

Graphics Processor Info: 
Metal: AMD Radeon R9 M370X
Init State: GPU for Image Processing supported by default with custom export support
User Preference: Auto

Application folder: /Applications/Adobe Lightroom Classic
Library Path: /Volumes/G-RAID with Thunderbolt/Pictures/Test Catalog/Test Catalog-v12.lrcat
Settings Folder: /Users/david/Library/Application Support/Adobe/Lightroom

Where is your orginal photo stored?

Are they in a network driver?

My photos are in a network driver, I meet the same issue like you.

But in my issue, the adjustment can be done normal.