Depending on the Slim model you have there is still potential to mod it according to console mods wiki. But this looks like quite an involved process to attempt. Even with this modded HDD I don’t know if it would be possible to try PSNBB.

Here you can see all the features it had to offer: https://youtu.be/afetcJgUafg?t=835 For me it is very interesting that is looks like the step in between PS2 and PS3 era.

I personally have that Bitfunx PSxMemCard and loading games of off SD card using it is a blast. For me it is also useful as I have 2 consoles in different locations - slim and fat so I can just bring that accessory when I want to play on either console. It is also a requirement for me to play as sadly the drives on both of those are yet to be repaired :(

Myślę, że warto odkładać pieniądze w jakiś sposób. PPK jest o tyle spoko, że się o tym nie myśli - bo pieniądze się odkładają jakby same i są plusy związane z podatkiem belki. Sam korzystam.