The alternative to Ryujinx... Is Ryujinx itself. And soon something else. It has been forked, archived and mirrored. Someone will pick up the project, even if just out of spite against Nintendo.
I have gotten so sick of Nintendo's shit that I have started cloning all of the emulator repos that I use. Thankfully I had pulled latest less than an hour before the repo was pulled. Others have beaten me to the punch for forking and re-hosting, but you can include me in the archive army.
Suyu is technically still being developed but whether or not anything comes out of that is a completely different story. The few devs left are unfamiliar with the code (all the yuzu contributers left out of legal fear) and have super ambitious goals (they want to do a rewrite because the original code was allegedly based off of a leaked Nintendo SDK) so it's unlikely it's going to get anywhere.
I'm hoping Ryujinx forks that pop up after this have more success. I am glad that Citra survived the Yuzu crossfire though, Lime3DS seems to be doing well.
According to Ryujinx developer and discord moderator Riperiperi, "[On September 30] gdkchan was contacted by Nintendo and offered an agreement to stop working on the project, remove the organization and all related assets he's in control of. While awaiting confirmation on whether he would take this agreement, the organization has been removed, so I think it's safe to say what the outcome is. Rather than leave you with only panic and speculation, I decided to write this short message to give some closure"
Seems like this was a deal done behind closed doors between the project owner and Nintendo. It's completely reasonable to expect someone else to pick up the project under a different name, using source code available from earlier forks.
Unfortunately, this will further splinter the Switch emulation development community, and cause any work that was not yet release-ready (such as features detailed by Riperiperi later in the same announcement as the one quoted above) to likely never see the light of day.