Okay this is just a Ragno headcanon/theory about his Tama
On Ragno's card it states that he had telekinesis instead of a Dragon Tama as a few people have pointed out.
I'm thinking that he may use his telekinesis to mimic a dragon Tama.
So in my theory he takes bits of the energy put out by other people's Tamas and mashes them together into one physical shape of energy molded after a Dragon Tama.
Or he does something similar but just with molecules around him instead of energy from the Tamas, as I am unsure of whether or not certain Tamas would put out energy like that.
Ragno is known to be an extremely good Gorotama player and is likely one of the best there, if not the best. Sugoi likely saw that in him early on and took him under her wing.
A Dragon Striker comes once in a generation, as the show has stated multiple times. Edina was the last generation's Dragon Striker and Edina was extremely close with Sugoi. Due to the two's closeness, Sugoi was probably driven by wanting to ensure that she trained the next Dragon Striker to honor Edina and follow suit.
Sugoi was aware that Ragno lacked a true Dragon Tama, yet honed the needed skills to be the Dragon Striker so she used his Tama to their advantage. She taught him and instructed him in working his Tama in ways that would make the public see him as this generation's Dragon Striker.
From what we've seen, Ragno is driven by being the best and always being perceived as such. He most likely had that mindset before Kal Asterock, and Sugoi brought that out in him even further to make him want to be the Dragon Striker even more. He was driven by the need to be a once in a generation glory that nobody else could live up to.
So when it was the All Stars match from season 1 and Ragno had just unleashed Dragon Fury onto Ssyelle, when Key's Dragon came out it easily overpowered Ragno's, which may have been a result of it being a disingenuous dragon.