VLANs & Link Aggregation on OpenWRT Managed Switch, Mesh AP on OpenWRT...extender?

Hi everyone!

Three months ago, I started my homelab from a OPNsense firewall-router and a NAS. Currently I setup my home network without VLANs -- I only have my router, NAS, only access point and some client devices. And now I want to expand my home network to IoT zone, User zone and Guest zone. I want to follow this guide because in my dream network design is quite similar to his setup.

Can OpenWRT handle VLANs and Link aggregation? Is it performs great? I am considering buying a second hand GS1900-16/DGS-1210-16 as a managed switch which can handle VLANs and Link aggregation to increase throughput to my NAS.

Also, I want to do mesh, not only for my devices but also for IoT and guest devices. I am using Wi-Fi 5/802.11ac. Is any extender or wall-plug devices (less cable less mess!) recommended as a OpenWRT dumb AP?

Thanks!

Edit: Not 802.11ax but 802.11ac