I'm ashamed to have this question, but here is my current config
4G Modem (D-Link DW 4G) -- <-> TP Link 1200 -- Switch -- Netgear Orbi (in AP mode)
--- --- --- --- --- --- --- --- --- ---<-> TP Link 1200 ASUS RT-AC68u
( I also have a Synology rt1900ac, with I don't use as I noticed network...