The only asterisk to that statement would be if OP was a Mac user. Using Firefox for reddit and youtube nets me 4 hours of battery life on a 2020 13 inch MacBook Pro, while safari will get my 6.5-8 hours with the same usage.
Blame apple
and Google, for not doing the minimum thing they could have done and served you the best encoding for the platform.
It is almost if the companies you actually give you money to (or eyeballs) do not care at all for your interests.
Speaking of Safari, maybe it's a matter of preference or habit, but for me it's has a very weird UX