Watch someone new to mixing try their first EQ swap and you'll usually see the same thing: they cut deck one's bass and bring up deck two's bass in the same half-second, like they're afraid of the silence in between. It sounds like a bump, not a blend, and then they assume the technique itself just doesn't sound as good as a simple volume fade.
The technique is fine. The timing is the problem.
A volume fade, one fader down and one fader up, works by removing energy from the room and adding it back. Every frequency in both tracks is present the whole time, just at different loudness. That's fine for two tracks that don't have much going on in the same register at once, but stack two full, bass-heavy tracks on top of each other at full volume and the low end turns to mud immediately, no matter how carefully you time the fade.
The EQ swap sidesteps that by handing frequency ranges over instead of volume. Deck one's bass goes out, deck two's bass comes in, and for a moment, only one deck actually owns the low end. Same for the mids, same for the highs. Both channel faders can stay all the way up the entire time, because volume was never the thing doing the work.
The swap only works if there's a real gap between "this band is gone" and "the other deck's version of that band arrives." Cut and bring in in the same instant and you've briefly got neither track's bass for a beat, or, worse, if your hands overlap the other way, both tracks' bass stacked for a beat. Either one is audible. The first sounds like a hole; the second sounds like exactly the mud you were trying to avoid.
A full band-by-band swap (bass, then mids, then highs, each with its own moment) takes roughly a bar per move, sometimes two. That's not a stylistic choice, it's the actual time a listener's ear needs to register "this frequency range now belongs to the new track" before the next handoff starts. Compress that timeline and you're not doing a faster version of the same technique. You're doing a different, worse technique that happens to use the same knobs.
Land every move on a bar line. Not "close to the beat," but on it, the same way the track's own kick drum is on it. A swap that's rushed by a beat and a half sounds sloppy even at the right overall pace, because the ear is comparing your transition against the track's own rhythm the entire time.
This is the entire reason the EQ-swap lessons in the app score against a real bar grid instead of "close enough": the app computes the exact millisecond of the 8th and 16th bar from each track's actual BPM, the same math a working DJ does by counting phrases, and only pays out a Perfect when your hand lands inside that window. Trying to eyeball "about a bar" is exactly the habit that produces the rushed swap in the first place.
If you're working through this on your own, the fix isn't a faster reflex. It's deliberately overshooting how much time you give each band. Count four full beats between cutting one band and bringing in its replacement before you try to tighten it up. It will feel absurdly slow the first few times. It will also, for the first time, actually sound like one track handing off to another instead of two tracks colliding.