Good luck, it's prolific throughout so many enterprises and academic institutions.
We might see some support start to materialise for OIDC as larger enterprises start to make use of e.g. AzureAD properly, but you're still going to see tons of universities especially running their own Shib instance. And larger enterprises are going to be difficult to shift off of SAML when they've had X years of experience with it and their supplier on-boarding processes are built around it.
The entire Jisc UK Access Management Federation is based on top of SAML, so that'll power the vast majority of academic resource authentication flows. You can argue that security is less of an issue for this use-case (particularly when e.g. Sci-Hub exists) but I think it's likely that once you have the infrastructure set-up for this it gets used for more and more services.