As mentioned Veritasium videos are very optimised for views not science, some are good some not so.
Also as mentioned Steve mould is a good UK alternative.
Other channels to consider:
Smarter every day (very infectiously excitable geek/ nerd/ clever clogs)
Breaking taps (Diy microscopy amoungst other thing)
Applied Science (Very in depth super technical science projects)
Stuff made here (Entertaining Engineering project eg balistic cartridge assisted baseball bat)
3blue1brown For pure maths videos that make your brain hurt but very well presented, wrote his own software to generate visuals for the videos.