I think this post answers most of your questions about Monero; as you can see when it comes to implementing Monero in any wallet interface, the complexity of the privacy solution it offers demands significant developer time. Even if someone did provide a PR to Trezor Suite, it would require consideration of the future maintenance and usability requirements, given that Monero presents significant complexity.
On a professional note, I would add that although it’s not advertised, I have developed a curriculum for Trezor Experts to use for onboarding people new to Monero given the additional complexities using the Monero blockchain presents, and I am committed to continue providing it over Trezor Expert Consultation sessions on request. Should you be interested in this curriculum for professional or personal use, I’d be happy to discuss further.