Planning my first small/medium business network overhaul

Let me begin by saying, I am a software engineer, my B.S. is in applied math, but I have worked the last few years in college as a sysadmin for a small company. Before moving into my new role as a software engineer, I have a big job of reworking the network while working with consultants to meet NIST 800-171 + CMMC Level 3.

I understand static and dynamic vlans, DHCP, and subnetting on their own, but I am having trouble planning how they should all work together.

I have 2 locations with new Sophos routers, the one smaller location just has 1 48 port L3 switch with a main VLAN and VoIP VLAN. I am planning the setup for the larger location that has 4 48 port stacked L3 switches, 1 48p distro switch, and 2 24p distro switches.

MY QUESTION: I have planned out which ports will have which VLAN tags, which ports will be LAG/ trunk, but do I need separate subnets within a single location? (Both locations are on different subnets) Also, we use Windows server 2019 for DHCP, how do I setup DHCP for different VLANs?

I also want to use LLDP for trunking ports where the VoIP connected to the wall and the PC connects to the VoIP, but would that require dynamic VLAN rather than static?

The core switches are Dell PowerConnect 5548 and my distro switches are Ubiquiti Unifi L2 gen 2.

Thanks for the help!