E20

Aoshida E20 is nice, maybe you can cop an EW300 on the sales that are coming soon

I'm not familiar with the ones you're comparing, but if you want a hard-hitting bass with an clean, non-muddy midrange, you should be looking at the KZ Castor Bass. The Aoshida E20 isn't all that bassy in the stock tuning, it's actually more bright-leaning. It apparently takes EQ very well, but I haven't got around try trying to EQ mine yet. I think it's a bit over-hyped, but it's a decent IEM that's fairly comfortable for a 2DD. It does look & feel more like a $5 IEM than a $50 one though.

It has no midbass though, so whether it's a true basshead IEM or not is very track-dependent. Even the impedance adaptor doesn't add much above 150Hz. Something like the 7Hz Legato is probably better if you want a ton of bass and don't care too much about potential muddiness in the midrange. The Deuce's big thing is being very clean sounding, with a ton of sub-bass, so it has a very "detached subwoofer" kind of sound. To get a true basshead tuning comparable to a consumer-tuned earbud, you're going to have to add a bass shelf with EQ really. For a cheap 2DD that's apparently capable of being a true basshead IEM with EQ, there's the Aoshida E20, but the stock tuning is actually more bright-leaning and definitely not basshead at all. I haven't got around to EQing mine yet so I can't comment on how well it does, but apparently it can take a pretty big bass shelf without distorting. The Legato is also commonly used with EQ and has better build quality, but I couldn't say if it sounds any better if both are EQ'd to the same target.

The 7Hz Legato has the *most* bass, but most people EQ it because out of the box it sounds pretty muddy. I returned mine for that reason. If you want to EQ then the Aoshida E20 is a cheaper option, although the build quality is quite cheap compared to the Legato. Still, could be a killer combination with a Qudelix 5K if that fits in budget (or the Legato as well but that's getting even more expensive). In that price range the Aful Explorer probably has the best quality bass out of the box. Also, one of my favourite IEMs is the QKZ HBB, which is only $15. It's not as resolving as the Explorer, but I prefer it because it has more natural-sounding tonality. Vocals on the explorer can sound a bit muffled and sibilant at the same time, although it's an excellent IEM in every way other than that. Also the Ikko OH300 which is like a more vocal-forward version of the HBB, with exceptional imaging/layering - and it's only $50 (maybe 40 if you can find it on sale, but they all sold out for several months and I'm not sure if it's back on Aliexpress yet, just the Ikko site at RRP). In terms of ergonomics the Aful is miles ahead of the rest. The Aoshida is probably the 2nd most comfortable. The Legato is nicely built but it's quite large. The HBB and the OH300 are both a bit chonky and cheap feeling, but still fairly comfortable in the ear - they just stick out a bit (don't feel as large as the Legato but all are quite wide).

As someone who PEQ's a lot- the Castor bass punch, specifically from Castor OG, can't be replicated with just EQ. You can boost the bass that is there but it will not be the same quality of bass. Zero has better sub-bass but the mid-bass is much less and even for sub-bass I prefer Aoshida E20 or turning up the bass on Yu Xuan Ji.

I'm just a budget guy, but empathizing with the basshead stuff. I add a +15 ( or more) shelf to my S12s and still not satisfied. Never heard the deuce, but use it as a baseline target on various sets. For $15 you can pick up an 80 ohm, which should make a big difference. I'm assuming you prefer avoiding eq for convenience. 15 ohms doesn't do it for me. Personally I add a couple DB of sub bass over the Deuce target together with a 75+ resistance adapter (eq and plugs are sonically different and not interchangeable). W/ this setup, bass on the E20 and Castor Pro is absolutely ridiculous, leaving the Legato w/ shelf and Rosefinch w/shelf in the dust. Both sub and mid.