This is a bit scrambled.

Both IPv4 and IPv6 have a spot in their headers to tell what type of traffic is being carried. This is a 1-byte integer called a protocol number.

The TCP protocol is protocol number 6. UDP is 17. ICMP is 1. All are carried over IP.

Both IPv4 and IPv6 have another spot in their headers to identify their version. This is where 4 and 6 go, but it's not the same as the protocol number field.

Similarly, Ethernet has a protocol identification field, "EtherType." IPv4 is number 2048 (0x0800); IPv6 is 34525 (0x86DD)

You are mixing different versioning systems. ICMP is protocol 1 inside Internet Protocol, where TCP is protocol 6 and UDP is 17 [0]. Internet version (as it named in rfc790) is defined with four first bits, numbers 1-3 unassigned and 4 is our IPv4[1] Technically ICMP is layer 4 protocol, but defined as integral part of IP [2]

[0] https://en.wikipedia.org/wiki/List_of_IP_protocol_numbers

[1] https://tools.ietf.org/html/rfc790

[2] https://tools.ietf.org/html/rfc792