Only a limited scope of site settings are sync’d not all options under settings are sync’d between browsers. The settings that you are mentioning are independent to each profile and won’t sync. It has to be manually enabled.
Thats just how the sync feature is built on Chromium. Its not possible to have the same profile on two devices. Each profile on each device is independent. Sync only enables ability to have certain things to be sync’d across devices. The ones you are expecting are mostly UI based changes that are not expected to be same on all devices that are part of the sync chain.
BOTH are Windows version 2004, OS Build 19041.541 w/ Feature Exp Pack 120.2212.31.0
Brave Nightly (use 99% & the chain origin, though I have your market version) Ver 1.17.3 Chr 86.0.4240.55, 64 Bit
FLAGS ENABLED:
Enable Reader Mode
Smooth Scrolling
SMS Receiver Cross Device
Experimental QUIC protocol
Zero-copy rasterizer
Tab Groups
Tab Groups Collapse
Parallel downloading
Enable lazy image loading
Google Password Manager UI
Secure DNS lookups
Enable SpeedReader
Enable Brave Sync v2
All Defaults are vanilla, as are the browser settings with exception of Crypto Wallet (the browser MetaMask variant) being set for my “Ethereum provider for using Dapps.”