Just to get a bit technical, you are talking about two different standards: HDMI and HDCP
HDMI is the physical connection and cable that connects the two devices. https://en.wikipedia.org/wiki/HDMI
HDCP is the copy protection protocol that needs to be supported by all devices to allow content to be transferred between them. HDCP works over multiple physical interfaces such as HDMI, DVI and DisplayPort. https://en.wikipedia.org/wiki/High-bandwidth_Digital_Content_Protection
Current versions of HDMI are:
v1.4/1.4a that supports HD and UHD at up to 3840×2160 (Ultra HD) at 24 Hz/25 Hz with 3D, but no HDR.
v2.0/2.0a/2.0b that supports HD and UHD at up to 3840×2160 (Ultra HD) at 60 Hz with HDR.
Current versions of HDCP are v2.0/2.1/2.2
AFAIK the Tivo supports HDMI v1.4 with HDCP v2.0 and the V6 HDMI v2.0b with HDCP 2.2.
To pass the TV signal from the Tivo to your TV via a receiver, the receiver will have to support HDMI v1.4 (but will not output 3840×2160 (Ultra HD) at 60 Hz with HDR) or v2.0 (v2.0 is backwards compatible), but more importantly HDCP v2.2 as this does not downgrade. If the receiver does any type of processing on the content (upscaling, etc.) then it can output to a different standard, such as HDMI v1.4 with HDCP v2.0 if this is all that your TV supports.
As other posters mentioned, an HDMI splitter that strips out the HDCP copy protection will get around this (but might be illegal).