I don't think having extra keys is ever a problem, at the very least. As someone who touch types incorrectly, I only use the b on the right side, so I set the left b to something else (a key I needed because it's in Japanese layouts but missing in ANSI ones). I've seen alice layouts both with and without it, so the fact that so many group buys and manufacturers include a second b tells me I'm not alone in wanting it.

If anything, I think the way to fix issues would just be adding more additional keys. Looking at some non-alice split keyboards, I see designs with 6 on the right and with 6 the left, so I'm sure there are people doing both of those as well. It seems that different countries teach different hands for typing that particular key, too. If there was a way to put a 6 on both sides, that would help more people use the keyboard.

Look up "Model F Labs." This is their reproduction of a model f buckling spring keyboard. This one has a JIS layout. The colored keys were ordered for unicomp (keys for buckling spring keyboards only fit buckling spring keyboards, not MX type switches).

If you like clicky switches, buckling spring keyboards are great, though you give up a bit of customization. The model F repro is pricy and requires you to be willing to do some problem solving yourself from time to time, but it's definitely my favorite keyboard to type on and it's QMK compatible. If you're new to buckling springs, I'd reccomend looking into a Unicomp keyboard (based on IBM Model Ms) which are less fancy but also cheaper.

This is a bit of a longshot, but while trying to reply to a DM someone sent me, I accidentally hit the ignore chat button. If you could send me another DM or comment, I would greatly appreciate it.

The keyboard I took a picture of is a reproduction of an IBM model F (brand new model F) in JIS. This was the keyboard that someone DMed me about, which is why I took a photo of it although I already have posted this before.

Also, the keyboard that can be slightly seen at the top is a wooting 2 lekker edition. If anyone's curious about it, I can definitely recommend it for gaming. The analog switches aren't a dramatic difference even in many games where they work, but they're definitely a nice touch and the switches are smooth and adjustable in many ways.