I've never used OCLP, but I did quickly skim some of the information some time ago to assist someone else. IIRC, OCLP customizes some settings in the PRAM/NVRAM, so you probably need to perform a PRAM Reset to prevent those particular customizations from interfering with the normal boot process of the firmware. Make sure to hold the PRAM Reset for at least three chimes if possible....for some USB-C models you may only be able to hold it for two chimes or some even one since holding it further just pauses the boot process or it just ignores the keys & resumes booting (USB-C Macs are weird).
Plus you need to make sure you Option Boot the laptop by pressing & holding the Option key immediately after hearing the startup chime in order to bypass the firmware from trying to boot the hacked internal drive (it is possible some small fragment of the bootloader remains on the internal drive). From the Option Boot screen you can select your bootable macOS USB installer or try pressing Command + Option + R to access Internet Recovery Mode....both options should completely bypass any remaining files on the internal SSD. If for some reason you cannot start booting into Internet Recovery Mode from the Option Boot screen, then power off the computer. When powering on the computer make sure to press & hold Command + Option + R immediately after hearing the startup chime to access Internet Recovery Mode. Pressing the keys too soon or too late may prevent them from being recognized.
You will want to make sure to completely erase the entire internal physical SSD using Disk Utility. Within Disk Utility you need to click "View" and select "Show All Devices" before the physical drives appear on the left pane of Disk Utility. Select the top most item which should be the physical drive listed something like "Apple SSD AP0256....". Erase it as GUID partition and APFS (top option). Quit Disk Utility and select "Install macOS".
FYI, it is not enough to follow instructions you find online or in YouTube videos. You should also understand every step of the process, plus have a plan on how to reverse everything later on. Most people online don't make their videos to properly inform people or take into consideration some of the issues people may encounter and most rarely inform people how to undo those changes. There is a lot of misinformation out there.
