Realforce RGB is not considered to be one of the better examples of Topre. The difference in housings seems to make everything a lot more rattle prone and harsh. Based on second hand comments I’ve read at least.
The HHKB might be one to try out, but I would highly suggest a Leopold FC660C if you’re considering an HHKB. I would say between my Realforce TKL and the Leopold, the latter was far better out of the box. In both cases, I opted for the “silent” version of the switches.
I have an HHKB too and it’s okay, but not as good as the Leopold.