Hy. Unfortunately, I can only help to a limited extent in this case, as I've never created anything with SEUCK myself and therefore don't know exactly, where to find these enhanced version. It's apparently called the SEUCK Redux engine, but I can't say much more about it. But there are a few online pages that mention it, for example here https://itch.io/c/2039017/enhanced-seuck-games-c64-pal-only or here
https://tnd64.unikat.sk/Seuck_Compo_2025.html
SEUCK Redux is apparently by Martin Piper, as can be read on this second linked page. So you could try contacting either Martin Piper, Alf Yngve, or Richard Bayliss (i guess, the email-address of at least one of the three, should be found on the internet). They should be able to help, as these three have already been involved in several good SEUCK Redux games (e.g. Zap Fight 2, Flying Cobra RX, Dark Force Redux, Super Silverfish, etc). That would be my tip here, because if you take a look at the highest-rated SEUCK games to date (for example, on Lemon64, sorted by highest rating)
https://www.lemon64.com/games/list.php?list_genre=Shoot%27em+Up&list_sub_genre=S...
the games at the top, are almost all such SEUCK games, that use the Redux engine. There are a few exceptions, but generally speaking, SEUCK games like this play better, because more can be implemented technically and these SEUCK games don't seem so monotonous in terms of gameplay.