RFC 8446, the TLS 1.3 standard, is almost exactly 4 years old, but in practice some clients and servers spoke TLS 1.3 (either the actual final protocol, or a draft that's equivalent except a parameter is different and the anti-downgrade is disabled in drafts) for many months before that too. Today about half of popular web servers speak TLS 1.3

So, you're describing today's reality as if it's a far off impossible dream that you're sure can't ever happen.