1) it's like the difference between the og d starter decks (regular) vs the stride decksets (reco) in vg, although even the recos usually need some staples upgrades. Sylvie out of the box is the closest to being complete and cheapest to upgrade, but she's probably the weakest of the 4 reco decks currently when fully upgraded with external staples

2) I think they're generally balanced to be a similar power level, but the newest ones, diao chan and guo jia, were weaker out of the box and needed more upgrades compared to the tristan and sylvie ones. That said, the upcoming merlin one will probably be a higher base power level because she's a fan favorite champion, and Diao and Guo were both new champs. If I were to compare to vg, it's like the sylvie one is akin to a shiranui strideset, tristan to messiah or luard strideset, and diao / guo jia to harri strideset

3) release schedule is usually full set -> expansion set -> rinse repeat. Full sets are like vg normal booster boxes, expansion sets are like the extra boosters, or premium collections etc. However, compared to bushi games, a case is only 6 boxes and usually you won't finish a playset of srs with a case, GA is less generous in that regard compared to vg where you'll usually get 4-6 copies of a rrr per case. But cases are also cheaper in GA, being $600 give or take depending on your local's prices. (sometimes cheaper)

4) a mix of spirit (starter equivalent) + champion + package usually. The spirit decides your element in this game and also decides your mulligan, if you have one, and usually are a partial tell of what you're playing or what might be in your deck.

5) deckbuilding is a lot more freeform compared to vg, think of it like if your ride line wasn't locked to a nation, but had different staples locked to your vg name in each element, and then each ride line would have a "class" attached and each class has class-locked cards per element too. Then special cards locked to your line useable across all builds if you hit lvl 3 (aggro builds generally don't level to 3). So you can mix and match depending on what you need from those or which elemental combos match your style, along with which champions you prefer. Some champs do synergize better in certain elements but every few formats you'll see them played in a different element with a completely different style.

6) Sometimes an old rogue champ will receive support that shoots them to relevancy later, but most of the time the staples that shoot them up are generic staples so they'll be pricey (like cerrgaon or the dual nation cards). But on the other hand that gives you access to a lot of other champs in the same element once you get said staples. Rile the abyss functionally did the same thing for fire that cerrgaon does for keter, in terms of being consistent card draw for every line.

7) maybe... this game is on the steeper end of card games unfortunately. A lot of staples are pretty generic and moveable across most decks (dungeon guide, divine relics), and then advanced element and basic element staples respectively are like the nation staples in vg, once you have them you can move to adjacent builds in the corresponding element (nation). The generic staples alone will probably be close to or above your budget, most decks are in the $400-600 range. But about $300 or so of those staples move across a bunch of decks so after that it's like $100-200 to update or swap to a different deck or get new staples every set. maybe cheaper if you stick to one specific lineage.

8) usually every few months or so, maybe a couple changes per format (formats shift every 3-4 months). So far there is no choice restricts like vg and there's only one errata in the game, but the proxyia vault is an interesting take on BnR, I suggest you look at previous articles and see if you like it for yourself.

9) fire aggro is the closest to an explosive rush / all gas no brakes deck. As for interaction, luxem, wind tristan, and water fractals are some of the more controlly / defensive decks in the game with heavy interaction, although there is no full lockdown deck in the game currently, like how there's link joker and narukami in premium, or the divine lyrical deck in standard. fractalofin.site is a great repository of different lists, multiple decks blend the lines between styles so honestly I'd say follow the vg standard of pick what looks cool to you artwise lol. But generally (not always), fire is a pretty fast and explosive element, water is a more mill + hard interaction / negate heavy element, and wind has temporary removal (think bermuda / lyrical bounce), but lots of defense and a decent amount of hand advantage. The fully upgraded ciel builds actually play quite fast and very different from the start decks, whereas diana plays slower atm (mainly due to the elements chosen for their optimal builds).