Is it normal that the world record seed for PS4 is no longer functional in version 1.21.6?

Yes. The game updates constantly and so does world generation. The same seed on the same version on the same platform should lead to the same world. If the version gets updated the seed will not lead to the same world anymore

A newer seed is viable and faster, although its more difficult due to the fact you need a fishing rod rather than snow.

Seed: -541714255396397480

V1.21.60+

Here's a video if you want to see the route, it works on Ps4 as well