This is the one I've been using. https://www.amazon.com/Onvian-Signals-Rechargeable-Waterproof-Bicycle/dp/B099PFTNBB/ref=mp_s_a_1_15?crid=ZPVNDE7NWUHE&keywords=bike+turn+signals&qid=1657406428&sprefix=bike+turn+signals%2Caps%2C316&sr=8-15

Comes with horn and alarm lock. Not sure how bright your looking for since you didn't post an image of how dim it was.

I second the bike alarm.

I have this one which can sound an SOS if you fall over (you have to turn the SOS mode back on each time you chabge the battery though) and can be hidden in a bag so it can easily be broken/cut off by a determined thief.

I also have this one which also acts as a tail light, turn signals, brake signal (lights up more when you decelerate), and backup horn (I recommend a dedicated one if you need one - there's like a half-second lag). Charges via USB-C too which is nice. I love it but I will say the remote's design is a bit prone to accidental horn presses in a pocket. It does have a nice handlebar mount option though.

Still, I've found both to be extremly worthwhile purchases - they go a long way toward scaring a potential thief into wondering what other tech might be on there (trackers, cameras, etc), are cheap, lightweight, very quick to "lock" your bike with, work anywhere...

They also can always be used in tandem with regular locks to great effect. At the end of the day, even the best locks can be cut fairly quickly. Anything that can't will weigh a ton (and probably still not be much better). But if any attempt to even touch it in the slightest is met with angry beeps and then the sound of a car alarm? Definitely a more complete package.

I use a very cheap cable lock because its light and simple along with one of these on my commuter. I've never have had a problem even in the heart of Boston, though I have heard the alarm go off before (possibly someone just bumped it, but it was probably doing its job).

All locks can be defeated/cut easily if one has the knowledge and tools (which usually isn't much). All attempts to make them not defeated easily add so much weight it gets ridiculous.

However I've found adding an alarm like this one (there's loads like them) is a total game changer. It changes things so that if they inevitably do defeat the lock, they won't be able to get away unnoticed. It also is good for situations like the built-in bike locks, where you're not needing it to be that secure, just secure enough and convenient.

I don't attach it directly to my bike though, because then a keen-eyed observer will know where it is to cut it off. I put it in my saddle bag, and since I have several bags on my bike they'd have a hard time knowing where the sound is coming from (or whether the sound is coming from the bike itself, which some very expensive rare bikes have).

Best ~$15 I ever spent. I'm now also getting this taillight which has an alarm included and turn signals and brake lights when you decelerate - I'm not getting rid of the other one though since the taillight could more easily be removed by somebody who knows about it.