I slightly disagree with you. The casino knows all the technical characteristics of the equipment you play on from start to finish. Ask how the casino sees that the player is using multiple accounts. This is found out not only by the IP address but also by all the fingerprints of the equipment and browser, including even MAC addresses. However, I agree that the casino does not know about the performance of your system or about the presence of viruses, which can also slow down not only your computer but also the network itself.
Wait, I think there is some contradiction here. If the casino knows the technical characteristics of the gambler's equipment, it can roughly estimate the system's performance. Isn't that right? Therefore, by comparing the characteristics of your PC with the recommended technical characteristics of the casino games, the casino can easily estimate the compliance of your equipment. That is, it can understand whether the gameplay will be stable and will proceed "smoothly".
Of course, this is only part of the picture, which will not allow the casino to see the whole picture, because the "dark" spots remain the Internet connection (quality, bandwidth), as well as the presence of malicious applications that you mentioned, and which will affect the performance of the system on which the gambler plays.