The link you sent seems to have some nice things. I look for rounded edges on all metal bondage. Chaffing can take someone out of the experience. All "pain" and "suffering" should be intended, not a side effect of poor-quality toys.

I have these https://www.eviltoys.de/produkt/stahlfaeustlinge-steelbondage/ in black (with the matching metal helmet). They are very comfortable, but yes, not for everyone. No one is getting out of there after the locks.

Shackles are fine, but I did rant on my blog about how much I hate "police cuffs." https://dominam.com/ask-m/are-police-cuffs-good-for-bondage-beginners/