Do not follow video guides, follow vita.hacks.guide if possible. Just downgrade, hacks aren't stable on 3.69+ and it will improve your console in a few steps...
To downgrade, make sure to use SKGleba's modoru. It fixed the problems on higher FWs. (I would recommend FW 3.60 so you can reinstall Henkaku easily)
After you downgrade, make sure to use reFOOD to play games 3.61+.
For piracy (or pir*cy as you like), you can use PKGj/ NoPayStation. They use the official links so no DMCA possible (as stated above).
Do not use maidumps/vitamins dumps, most of them aren't just vpks and contain some folders along with them but maidump in particular is very unstable and outdated.
If you find a clean VPK dump, why not, use VitaShell (It doesn't come with Henkaku, MolecularShell does and i would recommend to install VitaShell from it) to install it.
If you find a NoNPDRM dump, that's fine but you will need to use a plugin (which is required for piracy anyways, it's also called NoNPDRM).