All my transactional emails land in spam

Have you tested doing some very small sends of very clean, basic emails to a test group that should not be flagged as spam? This might help you debug if your ISP is blacklisted somehow or if the content of your emails might be responsible. I'd also run the spam check inside Braze and see if it highlights any glaring consistencies between your emails.

Email platforms will also review the subject and content of your emails, so if for some reason your subject line or content is leaning more towards promotional, there is a chance they will flag it anyhow. Not saying this is happening in your case but I have seen people try and send a sneaky promo in transactional emails and get flagged.