How to beat Gelora Bung Yagoo Stage?

[Sgtkirby45]

I have been trying for a long time and I still haven't beat this stage. Any tips or guides to do this stage?

[phenir]

This is mostly just general advice that will help on any stage.
First thing to ask is how far into the stage are you getting? If you can't get far, you are probably lacking upgrades from the shop, especially speed. Speed, damage, and health are the most important to buy but pick up everything that's cheap if you can afford them. Once you unlock stamps, you could try doing coin farming with IRyS or AZKi with greed stamp. Besides those, it mostly just comes down to skill (avoidance mainly) with a little bit of item choice.
You really can't go wrong with weapons (do try to get a super collab though, it's extra item space) but you should be a little selective on your support items since some characters don't benefit much from some items, such as beetle with any character that doesn't have any damaging skills, and some items are just worse than others. Some items I'd avoid are limiter, milk, super chat (unless it is super), headphones (unless super), full meal, candy, feather (unless super).
Always try to have at least one item for healing; bandage, sheep, or horns. I prefer bandage since it always heals you back to full given time, but sheep has a super collab and scales with your health as well, and horns scale with your damage (more damage=more kills=more healing) so there are pros and cons. Vampire stamp works too but it's really rare. If your character has a healing skill, that might also work but I find they tend to be on the weaker side and can't be fully relied on like healing items can. Also try to get at least one speed item; energy drink, ninja headband, piggy bank. More speed means being able to avoid hits more easily and avoid being swamped when enemies can run faster than you.
For build order, I like to focus on main weapon first then start getting other stuff but do pick up good items along the way like exp items or a healing item or the weapons for the super collab I am aiming for. If you don't have max fandom then you also have to squeeze in character skills. Some are better than others though so figure out which ones are actually helping you a lot (healing or damage reduction ones can usually wait).

[Six Of Diamonds]

Passives, passives, passives. I'd advise maxing out your passive upgrades.
Fandoms also work wonders, if you haven't unlocked those.
Also, experiment with food from Holohouse (another upgrade).

As for actual builds: I've found the most success with 2 healing items (Nurse Horns and Band-aid), Focus Glasses, and if you can get them Study Glasses and Beetle (depending on which character you're taking). For weapons I always grab Frozen Sea, but the goal with the way I run S4 is to be hitting everything on screen and then some. Stuff like MiComet, Elite Cooking (or the super), Rap Dog, Idol Concert (again, or super).

[Sgtkirby45]

I did beat it with IRyS greed stamp guide. Thanks!