This is the deck I took to German Nationals with a few changes with new knowlege from that tournament. It felt incredibly competent against most top tier decks, as board breakers feel very rewarding right now.
The version I played at nats was without Radiant Typhoon Vision and The Fallen & The Virtuous, but instead droll, scatter fusions and lightning storms. Droll and storm came up, but had the lowest impact of my non-engine. Scatter Fusion itself is now fully cut, even though they are 1-card starters- against so many decks playing Fallen & the Virtuous right now, it did not resolve often enough and was completly dead the few times I went 1st.
With the 6th card going second I very consistently drew enough engine to OTK and enough board breakers to secure board presence. Too much engine was bearable, as Gem-Knights can chew through a lot.
Visions proved themselves incredibly well, as drawing more breakers is great and even allows omitting a going-first gameplan somewhat. At nats I sided a Infernal Flame Banshee -> Nemeses Flag -> Nemeses Corridor -> Thunder Dragon Colossus line, which is powerfull if it resolves, but simply contained too many chokepoints to ever do so.
Right now, I'm considering changing or even dropping Fallen targets in the extra deck. Synchro Ecclesia is great as we do play a level 8 fusion to use her effect to spin a card, but I'm struggling to see the utility of the 2nd one (Albion atm), as I'm not planning on seeing that end phase if I OTK. It's another Super-Poly target at best. I think Forbidden Crown is a great side deck option for going first, as you can simply crown your own monster, live that turn and go pseudo 2nd right after. It's hella expensive though.
Few tidbits at the end, I cut the Gem-Knight Hollowcore to 1, as the second never came up. MST for the vision is too weak, so it went to the side. And no Scatter Fusions, as I can search Brilliant Fusion and don't play enough Gems in the main to resolve two.
Lots of words for someone who only went 5-4, but I felt 3 of those losses were mostly attributed to the pilot lacking matchup knowlege.