The PS Plus Extra lineup refresh for October 2022 wasn't quite as good as it could have been for PS5 owners because of technical setbacks preventing them from accessing three of the games. They were Assassin's Creed Syndicate, Assassin's Creed Chronicles: India, and Assassin's Creed Chronicles: Russia. While Syndicate remains unplayable via the service, the 2D treks to India and Russia have now been made available on PS5 via PS Plus Extra.
All PS4 games should be patched to run on PS5 at this point
This is a positive development. They might actually fix Syndicate so
1) it's playable and
2) the flickering won't give people epilepsy attacks
I'm pretty sure that I added Syndicate on the PS Store on the PS5 (through PS Plus Extra), not the web app.
Some unsuspecting person with epilepsy could easily suffer a seizure from trying to play this game on their subscription. Fingers crossed that they fix it.