Hdmi over Cat5e flickering with GS105v5 switch

This market is extremely cluttered - various technologies exit in the field.

Most basic HDMI over RJ45 extenders are not using real Gigabit Ethernet on the link cable - some 100 USD per port. Some advanced ones claiming HDMI over IP - these are using an Ethernet-like connection, but negotiate a much higher link speed on direct connections. 200...1000 USD per port.

Adding a switch into such a link - even if misleadingly shown on many packets or leaflets coming with many of these HDMI extenders - does limit the link to Gigabit, and leads to a much worse performance (if it works at all).

For HDMi over IP devices, there can be some success using managed switches (the makers talk of Layer 3 switches why ever), the feature required is IGMP Multicast support which requires to be enabled and workable on the switch. - the link data rates go up to about 8Gb/s, ways beyond of what a Gigabit switch can handle. It does in my understanding make use of a different encoding can't run over standard Gigabit switches. The reason why the standard Ethernet links are coming up is because Ethernet signalling is used.

Whatever HDMI extender product type you are using - the non-managed GS105v5 is certainly nof fit for such a purpose.

Even standardized products based on HDBase-T which exists in three versions , even if 10G, 5G, 2.5G, and even a 1G Ethernet PHY, requires more but a non-managed Gigabit switch. You need to know exactly what technology is in place. And for a reason, the ports are labeled HDBT and the like...