Merrell's makes a "barefoot" shoe that is minimalist in structure yet apparently fits like a normal shoe:
https://www.amazon.com/Merrell-Womens-G ... foot+shoes
If you like tai chi as much as you appear to, it might be worth investing in a pair of these or something similar to them.
I agree with those who say that too much grip on the floor is not ideal - not
bad, mind you, but just not ideal for learning. What I would add is that once you have the entire form down and are comfortable with it, the classroom shouldn't be the only place you're practicing it.
You're still likely learning the positions in the form, so what I'm about to say should probably be filed away for later reference; and in fact, if you forgot what I'm about to say entirely, it would do no harm either.
Depending on what you're working to achieve with tai chi, your choice of footwear may not be quite so important. I have a classmate who steadfastly insists on doing his work barefoot. He spent the vast majority of his martial arts training time learning Japanese arts, and appears to be of the opinion that the way the Japanese go about it is the way all martial arts ought to be done. He calls the instructor "Sensei" rather than "Sifu" or "Mr. Pavletic." It's hard to articulate, but when he does tai chi, it has the appearance as if he's somehow figured out how to translate the form into Japanese!
Then you have me, and I train in shoes. I use the cheap "kung fu" shoes with the rubber sole in class - I stumbled upon the right sock combination to make them fit well for me. But when I'm not in class, I practice the form in whatever shoe or boot I happen to be wearing. I do this because my focus is martial arts; and if I need to use tai chi as a martial art, I should be able to do it in whatever footwear I have on at the time, and in whatever environment I find myself.
Some are better than others; for example, low oxfords, "kung fu" shoes and sneakers like Chuck Taylors do better than combat boots, for obvious reasons. Likewise, some environments are easier to do the forms in than others - a gym, a studio or a covered public pavilion, for example, is easier than a gravel parking lot, the incline of a hill, stairs, or a sheet of ice on the pavement. The challenges present in the latter types of surfaces is a reason to seek them out, rather than avoid them - after you're comfortable with the form on an ideal surface, of course. It's also been my experience (though that of others may differ) that the differences in environment and surface are greater than any difference in shoe.
Anyway, the shoes above seem to recommend themselves. Maybe something similar would work for you.
Cheers!
gvi
The important things are always simple.
The simple things are always hard.
The easy way is always mined.
- from Murphy's Laws of Combat