While this Unlimited PS4 / PS5 Game Sharing Method is currently active complete with a guide and demonstration video below, before getting too excited keep in mind the loophole will inevitably be patched and closed by Sony as was done with previous PS4Scene and PS5Scene gamesharing methods... so NOT worth the risk in attempting them for most users. 
Update: As expected, this method has now been patched and no longer works. 
Proceeding all the early PS4 ModChip-Based GameSharing Methods and PSN Account-Based PS4 GameSharing Methods, here are some more previous PS4 / PS5 GameSharing Methods for reference also sorted by date with the oldest first:
Below are the latest Unlimited PS4 / PS5 Game Sharing Method Guide instructions via Pastebin.com and demo video from @rmorteza21p (Twitter) and @zecoxao (Twitter) for those interested:
New unlimited game share method (PS4 / PS5):
1. Log in to your account and go to the Divas section
2. Get the name of the relevant device (PS4 or PS5) and change it
3. Change until you get an Error Has been Occurred
4. Sometimes the account may not give an error, in which case at least 15-20 times the name of the account will be randomly tested on the console to be active.
5. If the account is not active and does not give an Occurred error, then click on the account on a console like PS5 that has the capacity and get active and de-start. Finally, start changing the name of PS4 and repeat the above steps.
Video:
As always, we'll update the article once confirmation is received of this PS4 / PS5 Unlimited GameSharing Method being patched.
Be careful with my unlimited sharing account method on PS5, now if you click on any profiles 'hacked' on your PS5, all the games are immediately locked.
You need .rif for get launched I think, so you need to have the games on your account.
Update #2: GameSharing v3 PS4 by @freeplex
Today I'd like to share one piece of information I've learned a long time ago on the PS4 gamesharing method. This has been working for a long time, like a couple of years now. I think now is the right time to share the method with love and good intentions. Gamesharing hardware PS4 (PS4 SysGlitch Tool / SysCon Glitching)
It work on last firmware old time!! Now work on 10.01


Proceeding all the early PS4 ModChip-Based GameSharing Methods and PSN Account-Based PS4 GameSharing Methods, here are some more previous PS4 / PS5 GameSharing Methods for reference also sorted by date with the oldest first:
- PS4 Gamesharing Guide
- XBox One Gamesharing Method
- PSX Download Helper: Transfer PS4 Game Data via PC
- PS4 Gamesharing Methods Outlined
- PSN Account Sharing Dumps
- PS4 Method to Activate PSN Accounts with Games
- New PS4 Gamesharing Method via Zecoxao
- PS5 Console Sharing and Offline Play
- PS4, PS5, Xbox Series Gamesharing Method
- PS4 and PS5 Unlimited Gamesharing Method via Remote Deactivation Bug

New unlimited game share method (PS4 / PS5):
1. Log in to your account and go to the Divas section
2. Get the name of the relevant device (PS4 or PS5) and change it
3. Change until you get an Error Has been Occurred
4. Sometimes the account may not give an error, in which case at least 15-20 times the name of the account will be randomly tested on the console to be active.
5. If the account is not active and does not give an Occurred error, then click on the account on a console like PS5 that has the capacity and get active and de-start. Finally, start changing the name of PS4 and repeat the above steps.
Video:
As always, we'll update the article once confirmation is received of this PS4 / PS5 Unlimited GameSharing Method being patched.

You need .rif for get launched I think, so you need to have the games on your account.

Today I'd like to share one piece of information I've learned a long time ago on the PS4 gamesharing method. This has been working for a long time, like a couple of years now. I think now is the right time to share the method with love and good intentions. Gamesharing hardware PS4 (PS4 SysGlitch Tool / SysCon Glitching)
It work on last firmware old time!! Now work on 10.01