Devialet - Mania

If i remember correctly, there are hi-fi adapters that can make any speaker bluetooth compatible, and allow up to 990kbps via LDAC codec. But apart from that, there are BT speakers close to hi-fi or are at least intended to sound similar, like the Devialet Mania, Harman Kardon Go+play 3, or some from Sonos, but they are hella expensive.

Yes, that's pretty obvious but they're probably still the best options. Only thing that could be better than that is BT speakers with 9 band eq's since you can make them sound however you want. Like, i have a lot of speakers, but my most preferred ones are the Earfun Uboom L and Soundcore motion+ because they have 10 and 9 band eq's. Obviously the hardware needs to be on point too, but that's the best audio you could get, AND the Soundcore also has a hi-res códec.

I’ve tried the devialet phantom I and mania before, but to be honest, I think they’re overpriced. It feels like I’m paying more for the brand and the aesthetic design than the actual sound quality.

Since u didn't specify budget, a small speaker that can pump out actual proper bass is only the Brane X and Devialet Mania rn in the market. Mania has a much more flat eq which may sound boring and unimpressive at first, but u will soon appreciate how pleasing a flat frequency response is and notice how u get no listening fatigue at all. Brane x is a warmer speaker that has a pretty bad bass drone that u will find annoying for long periods, as it lacks highs and mids, however it is extremely impressive in pumping out bass, that is properly audible up to around 20+hz, whereas mania gets to 30hz but with significantly better tuning(cons are it's price is stupidly expensive) Brane x is cheaper and produces better bass, with the sacrifice of lacking mids and highs which gives bass fatigue, Mania is more expensive, but has very consistent frequency response, smaller, and still has proper deep bass to 30hz no issues.