If you rely on the TCP checksum to protect your data you are delusional anyways. The TCP checksum is a simple additive checksum that is very weak and cannot detect wide classes of data corruptions. It is is well known that it won't catch many problems, with classical papers describing this. All it can do is to catch very obvious "big" mistakes.

That is why link layers always have other stronger CRCs too.

This is actually one of the better reasons to always use TLS. Yhe MAC authentication it uses is much stronger.