Looking to upgrade my network setup but I don't know if it requires changing any hardware

Hi friends. Over the past few years I've built out a very, very modest homelab (Synology NAS, MFF Optiplex and a couple of Pis) and with a growing number of IoT devices, etc. I would like to implement some VLAN segmentation. Plus it's a nice way to further my (absolutely lacking) networking knowledge. Right now my networking hardware is down to my ISP's modem and a GL.iNet Flint 2 acting as both router and access point.

I imagined a setup with 4 VLANs (Trusted, IoT, Guest and External for the very few things I open ports for) with wireless networks for the first three and . I started investigating if this was possible with my current hardware and somehow convinced myself that no, it isn't, and that I needed to pickup a managed switch. In reality, I think I could have just consolidated everything to the ports of my Flint 2 and ditched the unmanaged switch I was using. Checked out the options at my local Microcenter, saw they had a Ubiquiti option (Switch Flex Mini) for a reasonable price and thought "well, what if this is my time to dip my toes into the Ubiquiti world." Naturally that lead me to notice they were also running a sale on their Cloud Gateway Ultra and thought "wow this is really might be my time to get into the Ubiquiti world, I'll just use my current router as an AP."

And then I fell into the rabbit hole of trying to figure out how the hell to make that all work. And I don't know if I'm dumber than I thought, or this is way more complex or who knows. Setting everything up on the Ubiquiti side was very easy, on the GL.iNet (and even vanilla OpenWRT) side, not so much. As I've read more and more into it, it seems like there are many people who have wanted to setup VLANs on their Flint 2s, but very few who have actually managed to do so successfully.

So I've fallen afoul of the golden "buy once, cry once" rule and I want to make sure to take the opportunity to take a step back and re-evaluate just what the hell I have going on and what my expectations and next steps should be. I don't think the current combination of Ubiquiti hardware will get the job done, which is unfortunate because the software experience is immaculate. I think if I had gone with the Express 7 and the switch and ditched my Flint 2 it may have worked out better for my needs. And I'm still open to that option, but it feels so unfulfilling to give up on the idea that I could get this going with my current hardware. It seems technically possible, surely I'm just misconfiguring something or not finding the right info on line.

I'm not really sure even what my specific question is here, at this point. Any insights from anyone, experiences trying to do this with GL.iNet hardware? Frustrations with it? Documentation or tutorials to read? I'll take anything at this point, I just dream of obtaining deeper knowledge and a more secure network!