Penmachno loops 1 and 2 if you didn’t do them together? Penmachno is awesome, I want to go back (for the fourth time)
Could try Coed Llandegla black, Its like penmachno with some of the speed, but not as nicer place to be and not as imaginative or fun, the corners all feel the same, and the Red (to get on/off the black) was pants. All my own opinion obviously
Else have a look in the bikefax Snowdonia book.
Theres a ride in there that does a loop N/NEerly of capel curig. Another favourite of mine. After going through a farm/house early on on the first proper climb, and along the top wall after that, the Bway heads across a bog. If you head up the track instead, you can get onto the waterchannel (theres a path next to it) that feeds the resevior you’re heading to. Then take it from there. Really nice uppy/downy techy (but good fun) singletrack alongside the reservior, a hairy road descent (Bizarrely its rly good for a road, loads of tight corners, nice and steep, then back up another valley, with a really good descent back into capel curig. About 17 miles. I did this ride with my mum, and she really enjoyed it, so it can’t be too hard.
Not really like penmachno though. If you rode mbr? at brenin then it should be fine.
If snowdons not snowy, snowdon? Probably is though. I’m not local so don’t really know a lot else.