There are several important points to make turn2 work well
About the monster
There are several monsters that are important for turn2
The essential monsters are leo, karnal, riley, belial, gapsoo
Other important monsters are
giou, minato, xing zhe, aaliyah, bolverk, feng yan, juno, mei hou wang, haegang, nana, woosa, veromos, lutia, mo long. josephine, abellio, verde
The more important monsters you have, the easier it'll be for the turn2 team to work well
About the runes
Of course you need runes that are fast, but you don't have to use them for every monster.
You need to use a lot of vio and desp runes, so farming with dragons and giants is necessary.
To achieve higher ranks, you need to farm grind and gem with r5.
About artifact
Artifacts are important, but the quality of runes is more important.
My artifact isn't that strong, but I'm still able to compete in the higher ranks.
Each monster has its own options, but the priority is low.
About speed
The speed of the support monster needs to be fast.
Other monsters' speed can be low, but their hp, def, res, etc. need to be high.
For example, riley, aaliyah and other support monsters should be fast.
Until around season 10, it was possible to win even if all monsters were slow, but in recent seasons, it's not possible to win.
If the enemy team is the same turn2, it's possible to win, but if they are turn1 or CC team, speed is necessary.
If you don't get your leo banned, it's not a problem, but basically turn1 and CC team players tend to ban more leo.
So, to win in such a situation, you need a monster with high speed.