Network design/topology to deploy for clients who requires simple flat network that's reliable and cheap

I am not "certified" or anything officially. But I am from a computer science background, with a Bachelor's Degree in Computer Applications (doing my master's now).

I am confident to work MikroTik's RouterOS for routing/policy based routing, load balancing, firewalling etc to ensure reliable 24/7 connectivity.

So basically, I have some potential clients whose requirements are simple:

1. Single LAN subnet (No VLAN, single DHCP server, maybe two at the most on the router itself)
2. Likely they'd want an unmanaged switch
3. High-Bandwidth throughput for WAN (depends on their ISP[s] of choice)
4. 1G LAN is sufficient
5. Reliable Wi-Fi Mesh (consumer grade is what they prefer)
6. As cheap as possible

• This is where the issue lies

MikroTik's ultra-cheap routers comes with only 16 MB of flash and a lot of users on their forums have had issues with that. I have been thinking of sticking an RB450Gx4 to all of the clients as it has ample flash and storage + the arm CPU is as good as it gets with long-term software support.

The switch/Wi-Fi mesh/APs can be compromised in regards to their "We want cheap" requirements, but I feel I shouldn't compromise on a decent capable router.

What do you guys think?