Your website tip works. Simpler, use iPad Scan Text to drop the PIN without typing.
- Open Safari, go to roblox.com/redeem.
- Tap the PIN field, tap Scan Text, point teh camrea at the card. iPadOS 15+ supports this.
- Insert the scanned PIN, tap Redeem.
If the scratch area is rough, snap a photo first, zoom, then Scan Text from the photo. Fewer typos, faster than manual entry. I do this for Apple gift codes too. If Safari glitches, use Chrome on iPad. Same steps.