Managed switch with OpenWrt support or maybe new ax AP?

Regarding 'Supported' Managed Switch: do you mean actually running on OpenWrt firmware?
=> If running on OpenWrt firmware is desired then look here for more info

=> If running on OEM firmware is fine then you have plenty of options, ie.

  • Netgear MS108EUP (2.5 Gbps) or GS308E (1.0 Gbps)
  • ZyXEL GS1915-8 / GS1200-8 (1.0 Gbps)

In case looking for an additional Wifi router: