first off you want a hardmod on you og box and depending on your model you wouldnt even need a modchip
1,4 sharp models as example
softmod is subotimal since bios flashing and reflashing is not possible and changing / upgrading your internal hdd wont be possible since it married to you console
and for the modchip i would say you should go for project stellar
https://makemhz.com/products/stellar
and heres a perfect site to guide you to the whole process
https://consolemods.org/wiki/Xbox:Getting_Started