Hi Julian!
Basically the dock is having issues at the moment to be connected with your Switch.
Make sure you have the original Nintendo charger connected to the docking station.
If this is the case, disconnect everything from the dock and wait for 2 minutes. Then reconnect and try again.
If the issue stays, then try another dock (if possible) and check if the issues are solved.
Otherwise you could replace the dock it's mainboard to solve it.
Part: [link|https://www.aliexpress.us/item/3256808338511407.html?pdp_npi=4%40dis%21EUR%2119.29%2111.19%21%21%21155.56%2190.24%21%4021016e5f17507101691678998d2243%2112000045556179769%21affd%21%21%21&dp=EAIaIQobChMItvCP3M6MjgMVcJKDBx3tpDonEAQYBiABEgInePD_BwE&gad_source=1&gad_campaignid=21691866223&aff_fcid=c62a3525de6e4e258da6312c79009848-1750855968169-08377-_oEmQFg2&aff_fsk=_oEmQFg2&aff_platform=bops-tool&sk=_oEmQFg2&aff_trace_key=c62a3525de6e4e258da6312c79009848-1750855968169-08377-_oEmQFg2&terminal_id=c932d7c87f6843adb1b7e3af5aca7fcf&afSmartRedirect=y&gatewayAdapt=glo2usa4itemAdapt|1PCS Original Motherboard Dock Repairing Charging Board for Nintendo Switch / OLED HDMI-compatible TV Base Circuit PCB Mainboard - AliExpress 44|new_window=true] (those are not that expensive).
Please let us know how it goes!