HTTPS stands for HyperText Transfer Protocol, it is just the way that web servers handle requests from web clients such as browsers. It is a bit of a misnomer in the sense that it can handle any kind of data, even binary data.
The S stands for secure or SSL. It means that the HTTP connection is established over a connection secured by SSL or, as it is now called, TLS. TLS stands for transport security layer, it protects an otherwise normal port-to-port connection over TCP (the internet's transport control protocol) using cryptography.
TLS is just established before the HTTP connection, the secure layer is basically transparent to the HTTP connection. In other words, HTTP will work the same way regardless if the underlying layer is secured or not.
RSA is a cryptographic primitive. It relies on the RSA problem to be secure, using modular exponentiation as primitive for encryption or signature generation. RSA as such can be used as part of the TLS protocol to authenticate and to establish session keys. It may also be used as algorithm within the required PKIX based certificate infrastructure (RSA based certificates from certificate authorities).
In TLS 1.3 RSA is not used anymore for key establishment. It is only used to authenticate the server and optionally the client through the PKIX based certificate chains and a final signature generated by the leaf certificate belonging to the server or client.
RSA can be used within TLS 1.2 and earlier to establish the keys and to authenticate the server at the same time. This option to establish keys using RSA doesn't deliver forward security, so it was removed from 1.3 altogether. Client authentication is also still a possibility.
So are RSA and HTTPS the same thing?
No, both are very different. RSA is a cryptographic primitive while HTTPS is an application level protocol in the OSI layer definition. Even as concepts they can hardly be further apart. Yes, they both can be used to encrypt data, but that's where the comparison ends.
HTTPS may or may not use RSA; currently there seems to be a shift to elliptic curve cryptography over RSA because it is more efficient and secure. If quantum computers come of age, TLS may have to switch to post-quantum cryptography. In that case HTTPS may well be practical long after RSA or elliptic curves have become deprecated.
RSA is asymmetric as it uses public and private keys. HTTPS commonly employs both symmetric and asymmetric encryption, but at the message encryption level it just uses symmetric session keys. Asymmetric encryption may not be used at all on TLS session resumption or when TLS entity authentication is performed through pre-shared keys (PSK).
Note that I don't see the claim that RSA and HTTPS / TLS are the in the article at all.