Add All to Showcase is safe for most products, because Soco only ever adds links with the same or higher commission. The one exception is a higher rate Soco can't see, like a deal you arranged privately with a brand. Add All can replace that with the standard link, so leave those products out.
When to leave a product out
Leave a product out of Add All when you have a rate Soco cannot see. Soco only knows the standard commission shown in TikTok Shop, so it cannot tell that your link already pays more. This happens in two cases:
You arranged a higher rate directly or privately with a brand, so it does not appear as the standard TikTok Shop commission.
A brand raised your rate after you added a link. Soco checks rates only when you add a link, not continuously, so it never sees the increase.
In both cases Soco sees only the standard rate and may replace your better link. Keep your own link on those products.
How to keep or restore your link
To protect a rate Soco can't see, add your other links individually instead of using Add All, and skip that product.
If Add All already replaced your link, you can switch back right away. Add the brand's own link to that product again in TikTok, which allows only one affiliate link per product, so your new link replaces the Soco link automatically.