With a lot of PaaS type vendors you are effectively exposed to both the vendor themselves and the public cloud they run their stack on top of.
Broadly I think you're much more likely to be the victim of a platform-level breach involving an immature startup PaaS than a hyperscaler cloud, however I think for small teams the alternate risk you take on is that AWS/GCP/Azure are full of landmines and extremely easy to misconfigure in insecure ways if you don't know what you're doing. Especially if you have AI telling you confidently wrong things.
Broadly I think you're much more likely to be the victim of a platform-level breach involving an immature startup PaaS than a hyperscaler cloud, however I think for small teams the alternate risk you take on is that AWS/GCP/Azure are full of landmines and extremely easy to misconfigure in insecure ways if you don't know what you're doing. Especially if you have AI telling you confidently wrong things.