Where Do I Go From Here? Hangar Advice Wanted

Looking good Anon, +1 to the aphids on the stalker. And like stated above, a Galahad would do your playstyle and hangar good.

That Stalker needs to go. You can't get any damage with it, and it might get you 1 contested centre beacon before getting destroyed or severely crippled. Instead, start with the Carnage or Griffin if you want to grab an early beacon, and go for the MoC gold. So put 2 Magnums or 2 Aphids on the Stalker if you want to keep it, otherwise you'll need to buy a new bot.

Your second Leo, I would change to either 3x Punishers, 1x Thunder. Or change to 3x Pins, 1x Trident. Latter is prolly better, and it gives you long range. Punishers+Thunder do a lot of damage < 150m, but 150m - 350m is no man's land.

Your first Leo, I think it's ok. But the weapons don't match. Meaning the effective range of Thunder is < 150, while Magnum is < 350. Depending on what you do with your other Leo, look to replace one of them soon.

Your Griffin and Carnage can stay.

If you replace your Stalker first, go with either Gareth or Galahad. If you replace a Leo first, go with a Galahad.

First off, you did say you tend to play too aggressively. That's the first thing that needs to be changed if you want to move up the leagues. Be more patient, pick your spots, play to your bots' strengths and find ways to mask their weaknesses (e.g. your Zeus Carnage - I hope you don't stand out in the open too long, just because you wanna wear down the shield on the britbot you're zapping).

Second, it would be better if you matched weapons on your bots, because it then allows you to play a certain style on that bot. For example, your first Leo - it has a Pinata, which is ideally a pop-and-hide weapon, and Magnums, which is a long exposure kind of weapon. A third Magnum would maximize the effect better. Your Punishers too - although they're marked with a 500m max range, they're ideally used below 350m.

Recommendations - RDB Griffin is probably one of the cheapest solid builds you can get. Griffin + 2 PINs + 2 Tulumbas. This can replace your Trident Leo. Keep the PDB Griffin.
Stalker - lose the eCU. Either 2 aphids or 2 Pinatas. 2 magnums would also work to an extent, but I prefer Aphids, since it's not dependent on stealth ability to use. For now you can keep the Leo, but make it a Thunder with all Pinatas or all Magnums.

Lastly, what to save up for - if you really like the Stalker, I suggest Gareth. But personally, I prefer plasma Galahads - they're a really good balance of speed, toughness and firepower. They can be a bit boring, though. Orkans, too. If you do put together a RDB Griffin, best to eventually convert that to a DB Griffin. Very good hit-and-run bot. That should keep you busy for a while.