Yes, the UI in Slack is more cryptic after the update. I had some difficulties with searching for messages in the new design. I think you can't open the search results in context anymore IIRC. Also the change of color scheme. They didn't even bother to change all the icons to match the new color or they just made the change so quickly they didn't have time to.

[–] lemmesay@discuss.tchncs.de 1 points 11 months ago

oh, I didn't do any searching with new design. I extensively use search. it'd be bad if they break it. true for colours. their own colour scheme makes text difficult to read.
but I use custom colour scheme(Dracula theme), so have been spared of that.

seems like every year someone has to "redesign".