Disable Internet on VLAN

First of all I don’t have any Mikrotik device at hand to test any of my thoughts here so this is more of an conceptual question than anything I can test.

I am thinking of a dual RB5009 setup with several VLANs and VRRP for redundancy if one router goes down or needs a reboot.

In an ideal world I would like to be able to disable / enable all traffic to the internet on a VLAN by the push of a button in an app.
Such app could be either Mikrotik App or Home Assistant.
Let’s say I have a “WAN” Interface that provides internet access and I have a “VLAN 100”.

I assume I need a firewall filter rule to disable / enable access to the VRRP Gateway on “WAN” for “VLAN100”? Can I create a rule which can be enabled / disabled when needed or do I need to create a rule when it’s actually needed? Most of the time internet access would be enabled so it’s mostly about ad-hoc disabling access to the internet.

Could I do something like that via Mikrotik app easily (that would be a firewall rule which I could enable to disable access to the internet, I assume)?
As I have no Home Assistant Installation which I could use for testing either currently, maybe someone can help me out by letting me know if I could ad-hoc disable internet via a filter through this https://github.com/tomaae/homeassistant-mikrotik_router integration?

As I’m looking at 2 RB5009 I assume I would need to find a way to disable / enable the rule on both routers?

Any input is appreciated.