DHCP range limit and static DHCP leases

Hello, I recently got Pi-hole running using Pi-deploy on an old android. It's been working but I ran into a snag. I have it act as a DHCP server since my router doesn't allow DNS modification. However, it only has 50 IPs to hand out, and apparently there's more than 50 WiFi devices in my house. My family is very techy, so I suppose I shouldn't be surprised but still ... It's a lot of "smart home" stuff that really wouldn't benefit from Pi-hole.

So, my question is, if I have the Pi-Hole DHCP server active with it's specific range of IP and I set static DHCP leases for specific devices using those specific address, does that mean I can turn on my router's DHCP back on to handle the other various devices?

I should note my router does allow me to turn off ipv6 as well. So IPv6 addresses via router shouldn't be sent out to muddle things up.

TL:DR would this work?

Turn on Pi-Hole DHCP, set static lease for specific devices using MAC addresses and the specific IPv4s handed out by the Pi-Hole DHCP, turn on router DHCP but leave IPv6 OFF, let all the unspecified devices take on those addresses instead.

End result: specified devices benefit from Pi-hole while unspecified benefit from the regular router. Would this work? Because I only found one related post and it didn't mention IPv6. And I am still very new to all of this, don't... Really have any coding experience so I'm just working off what I can piece together from guides and reddit threads.

No, as there would be no guarantee which DHCP server's offer a client would prefer.
This could only work if your router would support denying a DHCP lease for given MAC address (namely the ones with a static lease configuration in Pi-hole).

You wouldn't be able to increase pool sizes beyond your router's subnet limit, but did you consider to increase Pi-hole's DHCP range to accommodate more IPv4 addresses yet?

What's your router's IP?
What's your router's subnet (something like 192.168.0.0/24)?

For a 192.168.0.0/24, you could set your range from e.g. 192.168.0.20 to 192.168.0.220.