OK, so as far as I can dig up, no, this laptop model never once has had support for a 2.5" upgrade.
So where you got your "supposedly" from has given false information.
This device was built for M.2 storage upgrades only.
I am trying my best to locate if this board has a thin header connection port on it for adding a 2.5" SATA connector, but it's not looking good.
If you want integrated storage, then you'll have to look into M.2 options.
If you want cheap storage, then you will need to go the route of external hard drive using USB 3.0 or Type C (the Type C port is located on the back)
If you want to look into external storage on your own that is fine, otherwise I might be able to help if you tell me what country you're in.
Otherwise, if looking on your own you have two options:
#1. Buy a pre manufactured external drive, more seamless and integrated into itself with warranties and such but tend to cost a bit more than option #2 depending on where you live and what is available for good prices.
#2. Buy an external hard drive enclosure and the drive separately, then put it together yourself.
Doing it this way can possibly be cheaper than option #1 depending on where you live.
But also, it allows you a few couple of freedoms:
#1. to decide between 2.5" and 3.5" as your hard drive format.
3.5" will be thicker than 2.5" but, the benefit is that you can get larger capacities at lower cost compared to a 2.5" hard drive of the same capacity.
(For example, a 2TB 3.5" drive can end up costing about the same as a 1TB 2.5" drive making it the same price but definitely giving more storage.....)
#2. In the event that the hard drive starts going bad and because of age and/or heavy usage, you can simply back it up, and swap out the drive itself with another one without needing to buy a whole new all in one unit, allowing you to reuse the enclosure, or even, use the enclosure as an adapter of sorts and have more than one drive storing data and having them put away in some kind of storage container and you can simply swap them out when you need to get to different data (not hot swappable though, drive needs to be properly ejected and unplugged first)