@win32ss, Can you please restore these flags?
(It worked fine in Supermium 132.0.6834.226 R5.02)

(!) [broken]
#bookmark-bar-ntp
{Never}
(Disable the Bookmark Bar on the New-Tab-Page).

(!) [broken]
#custom-ntp
{about:blank}
(Allows setting a custom URL for the new tab page).

(!) [removed]
#tab-scrolling-button-position
{Enabled - on both sides of the tabstrip}
(Enables buttons on the tab strip to scroll left and right when full).