I don't have much to go on, it has been more than 30 years since my arcade days. I've been making a list and am trying to prioritise purchases. I think Ikaruga will come first as soon as it is on sale again (which isn't very often).
I don't have a Steam account, but I'll try your method anyway to see how it compares to what is already on my list.
Sorry, but this is not what I need. I've seen this list and many similar to it. Just want a few names of games. Nintendo Life is a good resource, though.
Okay, but you can just pick a few games that look interesting there. It's not different than random people recommending random stuff here.
SEGA AGES Thunder Force IV
Tengai
Samurai Aces
ESP Ra. De. Psi
Mushihimesama
Espgaluda II
Deathsmiles I & II
DoDonPachi Resurrection
Dodonpachi DaiOuJou Blissful Death Re:Incarnation
These are pretty good, either from my personal experience or from reading lot of recommendations through forums and friends. The best Shmups on the Switch are mostly ports of existing older games. I'm not sure if you play on another platform too, I just read you have a Switch. I played on emulators on my PC and on Steam, there are a few more games I am not sure if they exist on Switch.
Crimzon Clover's really fun. It's similar to Dodonpachi.
Another good one is Ikaruga. It has an interesting mechanic we're you switch colors to absorb bullets.
Avoid Sine Mora and other "euroshmups", they just suck to play.
Sine Mora is not for everyone, but those who like it (like I do) _really_ like it. The gameplay revolves around the time mechanic and so does the really messed up story. The audio-visual presentation is great too.
There are several people who do not like it though, as it is a bit outside the box and is quite story-heavy.
Defender-like:
• Aqua Kitty UDX – cute, fun
• Black Bird – dark-cute
R-Type-like:
• R-Type Dimensions EX (and the others)
• Rigid Force Redux – ❤️
Classics:
• Blazing Star
• Thunder Force IV
• Cotton Fantasy
Other hori:
• Azure Reflections – Touhou fan game
• Sine Mora – time-mechanic ❤️ , not for everyone though
• Astebreed – switches orientation flawlessly ❤️
• ProtoCorgi – cute, hard
• Rolling Gunner – ❤️
• Zero Gunner 2 – proto-twin-stick arcade
• Galak-Z: the Void – strategic zero-G twin-stick, rogue-like-elements ❤️ (not to be confused with Galak-Z: Variant S, which is to be avoided)
• Assault Android Cactus – one of **the** best twin-sticks ever ❤️
• Jet Lancer – like Luferausers, maybe better ❤️
• Nitro Ball – classic proto-twin-stick arcade
Someone is selling Mushihimesama on my local marketplace. I know it is no longer in production or on the Switch estore. Is €55 worth it for this game? It is used of course.
Update: I see that it can be purchased new for 43 on different sites, so I suppose not...
Crimzon Clover, any version's good but World EXplosion is the most recent. It's a fairly difficult and chaotic bullet hell, but the novice mode should be reasonably approachable as long as you're willing to learn, and the design is superb.
Similarly, the whole CAVE backlog. Not all of them have novice modes or the like, and there's quite a few games not really available outside of MAME. The original DoDonPachi is/was considered the best starter bullet hell for a long, long time and still holds up pretty well, but is more difficult than a lot of modern games on their respective novice modes.
On the indie side of things: Star of Providence (formerly Monolith) is an indie roguelite bullet hell twin-stick-ish shmup with a pretty good amount of depth. ZeroRanger is a much more story-based game that I really enjoyed.