Not every brain works the same way, and everyone'e learning preferences are unique. My preference, because it underpins true understanding over rote memorisation, includes seeing connections and derivations from first principles. So that video, whilst effective, leaves a gap.
Here is how I was taught to deduce, not remember, the order of accidentals:
The major scale is constructed from 2 identical 'Tetrachords', each consisting of a tone/tone/semitone (W W H) and separated by a tone (W)
Consider the C Major scale
View attachment 4861880
and split it into these tetrachords
1: C, D, E, F
2: G, A, B, C
View attachment 4861881
Now take the second tetrachord, G, A, B, C, and put the first one on top. Notice how, in order to maintain the tone/tone/semitone order of intervals it is necessary to add an accidental to the new leading tone - the F from C becomes F# in G:
View attachment 4861883
Take that accidental and put it in the key signature:
View attachment 4861893
Continue in similar fashion, so starting on D this time:
View attachment 4861894
becomes...
View attachment 4861895
and so on. In the case of #, see how it is always the leading tone that gets the new accidental. See also how, for each additional '#' the new Tonic is the Dominant (5th) of the previous key. Hence the name - Cycle (or circle) of 5ths.
A similar process applies to the 'flat' keys, but here the process acts in reverse, so the new accidental is applied to the leading tone of the starting key, then transpose the whole lot down a 5th, which is the same as up a 4th, hence the name - cycle of 4ths.
View attachment 4861897
Following this proces is it easy to see how C becomes F becomes Bb and so on through the cycle of 4ths.
Armed with this knowledge you don't need to remember by rote. If you forget or you are not sure, you can work it out for yourself at any time. Do this enough times and you end up with knowledge supported by understanding, which is better, IMHO, than a bunch of fading memories.
YMMV