As I am sure you are finding, your provider probably has many features you might want.
With many VOIP adapters and phones, they leave it to the voice provider to handle all sorts of options (just like the phone company used to do). Yes, there are still answering machines and so on, but they are mostly for landline connections and you pay for all those addon devices, even if the option like a recorder is built into the cordless phone base or a separate machine. You are usually stuck with what the company decided you should have and how it should work.
The nice thing about VOIP providers is that you can swap them out for one with different options and those options are software controlled.
No telephone hardware or software in the phone can handle all the things I can throw at them.
I personally set up a VOIP system with a coffe farm which gives tours and had two buildings/offices. Here is what I programmed, and you can see, that no phone itself could do what we finally ended up with. Almost all functions are done outside he physical phones (2182's by the way).
A call comes in and the automated attendant grets them and asks which option they want. Those options are 1) Get tour information, 2) Get directions, 2a) directions from the North, 2b) directions from the south, 3) book a tour [rings a line on multiple 2182s which can handle the tour booking, 4) get general farm information, 5) connect to the coffee club to speak wih a represenattive to change orders, etc.
Option 0 allows them to get help (a human). If they press 0 the system checks to see if it is during business hours. If it is, then a ring group rings multiple phones in building 1. If nobody answers within 3 rings, then another ring group is activated and rings both building 1 and building 2 phones. If the request to speak to someone had been after business hours, the call is forwarded to voice mail. That voicemail is forwarded via email to the appropriate people. The voicemail for the coffee club and other extensions goes to the appropriate voice mail boxes and then is also emailed as appropriate.
So yes, the above is all complicated and very specific to that coffee farm. All those functions are done in simple software changes at the Voip provider and can all be done via computer from anywhere in the world at any time. Imagine trying to find a hardware soultion to that. Even our local landline telephone company cannot do much of what I configured. In fact, all that configuration and directing of calls and so on is free my my provider. The local phone company charges an arm and leg to do a small part of that. I *COULD* do all the above with a piece of hardware or by configuring my own PBX hardware or software, but why go with a physical piece of equipment if a provider will do it sall for free and maintain their hardware and software for me?
Yes, all that is way more than what you were looking to do but as you get into VOIP you may well discover things that you can now do.