Yes, I can confirm ViaBTC is plagued by bots. They're offering to accelerate 100 transaction per hour but even if I refresh the page at 10:00, at 10:01 there are no free spots left. Due to ordinals/brc20 spam ddosing the sh*t out of the blockchain my transactions are sitting there 10-20mb from tip for days, even though the fees are quite ok (~100sat/byte).
A week ago I attempted to script a ViaBTC transaction broadcasting automatically using shell script, it was to wait until e.g. 8:00 sharp and then send a CURL request which I dumped from Google Chrome, the problem is that even that is not working because it complains about invalid captcha. This is despite the fact that I also copied the captcha headers and made sure they were fresh. So I don't know how these bots manage to do it really.
Even worse that it's ORDINALS transactions being broadcaster out of all things, you know, the very transactions that caused this mess in the first place.