1. Launchers? Oh yeah, I'd recommend the Red Dual Rotation launcher that comes with Master Diabolos, it has a really nice, long string, and is pretty good at retracting, just be careful not to pull too hard on it. If you want something that's even better, but doesn't have the same dual spin mechanism that the Master launcher does, I'd suggest you go ahead and pick up the latest Sparking launchers, the red and blue ones come in their own box, and as the name suggests, if you pull the string hard enough, sparks will come out, and don't worry, nothing will catch on fire, trust me. The black sparking launcher is in the Variant Lucifer bey box. If you prefer ripcords, you should definitely get the Venom/Erase Diabolos launcher, The Ace/Rock/Grand Dragon launcher, or the Revive Phoenix launcher, all pretty good ripcords and their dual rotation, and for
2. The beys that are definitely worth buying are Rage Longinus, for every. single. part. The rage ring is outstanding when it comes to smash and upper attacks, by far one of the most competitive beys as of now, and probably for the future of burst too, the 3A Chassis is super bulky and has incredible upper attack power and is one of the heavier Chassis too. The destroy driver is a must-have, an absolute must-have, the driver is a star shaped flat driver, meaning it can get to decently high speeds if you launch hard enough, and has a bit of stamina even when spinning slow, but what's even better is that there's a free spinning plate around it meaning when it falls over, it'll just hit the free spinning ring and keep spinning for more LAD, meaning if it doesn't get a burst finish, you can still get an outspin. Destroy on Rage Longinus also has a red, gold spring meaning it's tighter than most drivers. Super Hyperion is another really good bey, the ring is great for upper and smash attacks, the 1A Chassis is the heaviest chassis in the metagame besides Variant Lucifer´s 2D Chassis. The Xceed driver on Hyperion is insanely good for attack, and it's free spinning meaning it's even faster than pretty much almost all of the rubber drivers besides Evolution which is on Cho-Z Valkyrie and Brave Valkyrie, speaking of Brave Valkyrie, Brave is another great bey to have, it's 2A Chassis is completely rubber meaning that it can attack pretty hard with that extra friction on it's side, and most of the ring is rubber too. World Spriggan is just an absolute beast and counters almost any Rage Longinus combo, It has a metal chip, and the ring can flip from right to left spin, right spin mode is decently good, but left spin mode is just insane, the chassis can switch from fixed attack mode, to free spinning defense mode. The driver, Unite, is similar ro CS/Coat Sharp from MFB, but a bit worse, that's all it is, it's also a dash driver meaning it has a gold spring with red paint on the top. Tempest Dragon is another good one, but honestly you'd only want Tempest for the base, and maybe the chassis, which has teh same Chassis as Hyperion, 1A, but it has worse teeth and is blue. Tempest is supposed to be an attack base, but works insanely good for defense/stamina combos in same spin, and opposite spin too. Lucifer is good for the 2D chassis which it's gimmick is that 6 rubber blades/tongues pop out, creating a barrier, but it's horrible against same spin because of the high friction of the rubber, but 2D is just.. too good in opposite spin because of the rubber. I don't think i've ever seen an opposite spin battle where a bey with 2D has bursted. Mobius is a good LAD driver. There's more good beys too like Glide Ragnaruk for the ring and the wheel disc, Jet for the ring and disc, and Lucifer The End for the driver, and layer (maybe) and Union Achilles for the popular Xtend+ driver.
3. Stadiums that should be grabbed would be the standard TT stadium, but it's too small, then there's the SuperKing Stadium Set, which comes with King Helios, and Super Hyperion, and the stadium is bigger than the previous ones, there's also the Limit Break DX set with Hyperion Burn and Helios Volcano, but it's really expensive and the stadium, in my opinion, isn't really that good, but it's bigger than the 1st SuperKing set stadium by 2-3x. It's just too sloped and attack type beys just slide out of the pockets easily, and the center is too small and attack beys just have such a huge disadvantage, unlike Stamina and Defense types, i feel like balance types have a disadvantage in this stadium too. There's good hasbro stadiums too like the Snake Pit set stadium, The Ultimate Tournament Collection Set stadium, The SpeedStorm stadium, the SpeedStorm Set Stadium, and if you want something smaller but still good, there's the Epic RIvals set stadium, and more, but i forgot the names.
4. The trends in the current meta are usually opposite spin spin stealing LAD combos, quick, fast, hard attack combos with rubber drivers, and pure stamina/defense combos, not sure about Balance combos anymore, also more about accessories, you should definitely pick up the Z Achilles Xtend+ Set if you want more than 1 Xtend+, but you'd have to get Z Achilles itself to make Xtend+, but the launcher in the set is right spin only, but has an amazing grip, and power trigger, there's also the Geist Fafnir Proof set, which is the same as the Xtend+ set, except that Proof is a frame, and there's no power trigger, and it's a left spinning only launcher. You can get the older burst grips too. Good sets would be getting the SuperKing Triple Booster which comes with amazing parts like Tempest Dragon, Curse Satan which was ONLY in a random booster, and the Naked layer base which was also ONLY in a random booster, and the Goku weight which was once over $200, there's a new driver called Wave in the set too, it's pretty okay for competitive, but a fun driver, it's also taller than most drivers.
Here's some trusted websites for burst beys -> MFB.
Beysandbricks.com
Ever-Wish.com
MallOfToys.com
ThePortal0.com (Most expensive site but free shipping)