How do I transfer my PS4 save game to the PS5?

Until recently I played the PS4 version of Crash Bandicoot 4 Its About Time on the PS5 on March 12th the PS5 version came out and it says there! No cloud save is available. You must first upload one from the PlayStation®4 game's save screen. Can someone help me? I don't know what to do

To clarify again:

I played the game on the Ps5 before the Ps5 update came out

So it's just about how I transfer the score played on the Ps5 from the Ps4 version of the game to the Ps5 version of the game

Turn on your PS4 and PS5 consoles and connect them to the same network via Wi-Fi or a LAN cable.
On the PS5 console, go to Settings> System> System Software> Data Transfer> Continue.
Select the PS4 that you want to transfer data from.

Source: ps5.com

On the Ps4: Settings> Management of the data saved by the application> Saved data in the system memory> Upload to the online memory

Simply select the game, then the file and upload it. But for that you need PS Plus.

Not effective.

I played the game on the Ps5 before the Ps5 update came out

I played the game on the Ps5 before the Ps5 update came out, so it's just a matter of how I transfer the score from the PS4 game to the PS5 version

?

I wrote a guide on how to upload the score to the Ps4?

I don't even have a Ps4

I played the game on the Ps5 before the Ps5 update came out, so it's just a matter of how I transfer the score from the PS4 game to the PS5 version

Oh, actually the file should then be on the Ps5.

Somehow not

You just have to do what I described in my answer on the Ps5. What's so difficult?