It may sound silly, but the tone in which you say something can either play the professional status up, or it can bring it down. You can’t change what your voice naturally sounds like, but you can work on controlling it to make sure you sound calm and collected when recording your message.
You don’t need to have your whole life story in your voicemail greeting, you just basically need them to know that they reached the right person and that you will be getting back to them as soon as you can. This is the part where people like to get funny, maybe by saying, “hey, I’m out and definitely avoiding you,” which is funny if your friends are calling, but not if someone you want to work for is trying to reach you.

It makes sense to have an after-hours / weekend voicemail greeting for important teams at your business so that your clients feel confident that they will be taken care of. You may also suggest alternate resources like a help forum, knowledge base, or online chat to support customers while closed, if available.
It’s a good practice for each of your team members to have their own personal business phone numbers. There are many reasons why they shouldn’t use their personal cell phone number for business, so you’ll want to give them their own phone number through your VoIP provider or phone system.