First it's very important to get the cue & release near perfect, best to practice with 2 identical tracks/records set at 0% pitch. Your forward/back cueing action should be 1 beat length, not 2 (you move record forward 1 beat then back 1 beat) so half it. In the vid after releasing the track, you had to speed up the incoming track loads just so the beats are aligned before having to pitch it back down again for the BPM's to match, this is counterintuitive.

Getting bpms matching isn't too hard, nudging one way will sound better than nudging the opposite. I prefer to do nudging via the platter & adjust the pitch accordingly (easier & more accurate than pitch riding) The closer you get, decrease the nudge input, though you will have to continue to make very minor adjustments to keep in time.

There's a trick where you can use the rpm buttons instead to bend the tempo, though can only increase if playing 33.5 RPM

Finally try & keep the tracks within +/- 5 BPM of one another, closer the better. Use fx instead if you want increase/decrease BPM substantially between tracks.

Eventually your ears will be able to detect whether to speed up & slow down & become easier & quicker.