RoomEQ and Crossfeed are features that came many years after all products had already been designed and released to the market. They require a dedicated DSP chip, which you find only in products that have been designed to support FX.
Some products even needed a small redesign using another DSP chip to provide the necessary capacity.

A bit insulting? Well, RME improves its products and adds excellent features where it is possible, and this is done free of charge for customers.

Just for your information, the HDSPe MADI FX is the only card with DSP/FX. All other PCI/PCIe cards do not have DSP/FX.

If you want RoomEQ then you should migrate to USB-based products like UCX II, 802 FS, UFX II, UFX III, and XT II.
From a price perspective, the UCX II would be the ideal product.

If you want to stick with AKM converters for analog I/O, then the 802 FS, UFX II, or UFX III.

Alternatively, a combination of UCX II and a reference converter like the ADI-2 Pro FS R BE for your monitoring. Then you have with the UCX II: TotalMix FX and features of the flagship interfaces like DURec, Autoset, mic inputs with a 75 dB gain range. The ADI-2 Pro FS R BE gives you the best features for monitoring (4 different analog stages, auto reflevel to automatically select between them to keep SNR/dynamic range as high as possible over a wider volume range, dynamic loudness, PEQ, sample rate converter, state overview, support for balanced headphones, etc).

Another (costly) alternative, if you want to stick to PCIe, is the combination of HDSPe MADI FX and a reference converter, connected through AES, such as ADI-2 Pro FS R BE (or ADI-2/4 Pro SE). Sure, this is a bit overkill (similar to XT II), because of the feature set of the HDSPe MADI FX with its three MADI buses, but that would be the only possibility to stick to a PCIe card as a foundation for your setup.