The standard NanoPi R4S (4GB without eMMC) running OpenWrt is a perfect device for your requirements. It handles Gbps SQM just fine.
You don't need to use an OpenWrt compatible managed switch of course, but I find it convenient to have all my networking gear running the same OS. I've been running an R4S with a Netgear GS308T switch currently flashed with OpenWrt 22.03.4 for some time.