Small Business Network Redesign with 2 DHCP Servers

I'm the only software developer and IT guy our company so bare with me as this is still new to me. We are a manufacturing shop with just under 50 employees.

We currently have a Windows Server VM handling our DC, DHCP(the only 1 currently), AD, and DNS. I am introducing a firewall to provide extra features to our network including segregating our network(have a separate guest network, plan on having more).

I've created a quick diagram of what I want to accomplish: https://i.imgur.com/yVkzJMg.png

Since there will be 2 DHCP servers (pfSense firewall) and Windows Server, how do I make sure that new machines in the same VLan as the Windows Server will receive an ip address from the windows server DHCP and not from the firewall? Or how do I improve this design? I also want to make sure that both access points can be used to access different networks(the main one or the guest one).

Hopefully I provided you enough information and that you can lead me to a resource to better understand how to solve my problem. Thank you all!