I use this Flag to have a nice scroll bar.
You can also use the ones you use, but that are hidden. Personally I prefer the ones in the first image for convenience.
You can search for them here: brave://flags/
I hope this information is useful to you, many of the requests for new features (in plural) are in the testing or experimentation phase. There is a possibility that they are not in Brave Browser, since I use Brave Nightly, which is where they release possible updates before reaching Brave Beta or Browser