One modem → 2 routers, separate subnets (1) CC Machines (2) DVR w/ remote access

Hi, I have read for hours on but still don't know if I understand it correctly. Please please please explain in simple terms if this setup is a viable solution or if I am misunderstanding and need changes. I really appreciate any advice. THANK YOU! (also...please don't suggest a totally unrelated solution like vlan or vpn, etc.) I should mention, I am basically giving up on setting this up myself, but I want to make sure that I can confidently go to vendors for bids to make this thing work and reject over-the-top expensive solutions in lieu of this setup using mostly existing equipment. $$$ is paramount.

GOAL:

1. We have a DVR that we want to access remotely, which currently works with port forwarding. it is not secure.
2. We have credit card machines that we want to make PCI compliant and separate from the DVR

PLAN:

▪ Here are links to diagrams of the proposed vs. current setup. The current setup was like this before I came around! Look at this first :) Current Setup Diagram LINK → Proposed New Setup Diagram LINK

▪ the plan is to using 2 routers to put the credit card machines on a separate subnet --▪ Router 1, Subnet A, serving the DVR and providing internet via wifi to various devices as shown in diagram (3 or 4 computers and 5-10 phones or tablets.)

▪ Router 2, Subnet B, serving 5 credit card machines via Cat5.

OTHER INFO/CONCERNS:

▪ I don't understand if one of the new routers in the diagram can be eliminated given the modem from the ISP has 4 ethernet ports and wifi built in.

▪ We pay for static IP which is used for remote access to DVR

▪ Router 1 is priority during the day and router 2 is priority at night. Here is the reason why--

(a) this is for a high volume bar, so it's important that the credit card machines work fast and all other internet traffic is low priority at night. there can be quite a few users on the network at the bar. currently, there is no QoS or anything managing bandwidth, and the credit card machines speed is not always reliable and frustrating.(b) During the day, when the bar is closed, the credit card machines are not used, and it is important the internet is fast for the people working in the office who are not present when the bar is open.