Need help with guest vlan/wifi solution on local LAN

Hello guys,

I am looking for an advice here.. I am kind of lost tbh.

I am managing small network in my free time and I am trying to create guest wifi on the floor of a building which would be using different VLAN than the local LAN other devices are using..

Some solution that would make the internal network (vlan1) secure from clients using guest wifi/vlan99

This is the diagram of how it is connected and how I'd like it to work.. however, it doesn't :)

https://i.imgur.com/UYhcQB8.jpg

RV325 residing in the server room on the bottom floor has two vlans created and untagged vlan 1 and tagged vlan 99 on the port where switch on the floor is connected, inter VLAN routing is understandably disabled.

The RV215W simply cannot access the vlan99, however, when I am connected to internal network, I can ping the dhcp server running on RV325 for vlan99...

The RW215 has only one ethernet cable connected to it's lan port, I set up two vlans with same numbers 1 and 99 and same subnets as on the main router RV325 of course, fixed IP for both were set up for the router in unused range by dhcp server (150+).

Both vlans had DHCP relay set up so the wifi clients would get an IP from RV325 directly.

The internal wifi worked fine..

But the Guest wifi clients connecting to it never got an IP in vlan99 and therefore couldn't access internet.

I tried also connecting it to WAN port, which effectively made the guest wifi to work but also understandably made it possible to access LAN devices..