Nope. Whilst that's how TLS_RSA_WITH_AES_128_CBC_SHA works, this not how Forward Secrecy enabled suites like TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 work. Most sites (and certainly any sites that think they're "secure") thus are not affected in this way.
In TLS 1.3 all suites (such as TLS_AES_128_GCM_SHA256) have forward secrecy so it isn't even explicitly called out.
In these modern modes (and in other modern protocols like SSH) the two peers agree random ephemeral keys (these days with Elliptic Curve Diffie Hellman) and long term private keys are only used to sign things to prove who you're talking to over the resulting securely encrypted connection.
So if you break RSA you can forge those signatures but you can't decrypt messages sent to and from the legitimate owner of the keys, those were, as your parent explained, secured with AES and not RSA. You would need to perform a live active attack, a MitM to interpose between the real server and its clients so as to decrypt all messages in transit.
