Some great recommendations from industry folks already.
But if you're not frequently in such high volume environments and you want something for the occasional concert you may want to start with cheaper options.
Don't take your hearing for granted - hearing loss is disabling and isolating - whatever you choose it is important to have something comfortable and convenient to carry that you will use and is up to the demands of the environment you'll be using them in.
I have Eardial for concerts (1-2/yr if that these days). ~$30. They are very comfortable, fit well (even though most earbuds pop out of my ears), easy to clean, and have a small clip on carrying container. Manufacturer says 11db reduction. Great for music but conversation in crowds is a little muffled. I've had them for a few years (prepandemic) and there's no sign of deterioration since they are lightly and gently used.