Alternative to Mail App?

macOS and Mac Apps

Until recently, I've been perfectly happy with the Mac's default mail app. In fact, maybe I'm just inept, but it was the most accessible mail client I'd ever had the pleasure of using, at least for my purposes, which are fairly simple.

However, recently my Mail app has started crashing a couple seconds after startup, no matter what I do. I've tried several fixes, all without success. Short of reinstalling my whole OS, I was wondering if there's just another accessible mail app I could use instead? Preferably free, but I'd be willing to pay a little if it's worth it. All I really need is the ability to have multiple accounts, and of course being able to auto-fill addresses based on my contacts and what's in my inbox is always nice. I don't do much with groups or anything like that, so my needs are really pretty simple. Any recommendations?