Are the Cheap "All in One Tablets" and Good?

I found these two on eBay:
First one: https://www.ebay.ca/itm/156846156204?_trksid=p2380424.m570.l5997&ul_noapp=true
Second one: https://www.ebay.ca/itm/156816567494?itmmeta=01K1RVEST798YYGBVKB3138JHW&hash=item2482feecc6:g:49IAAeSwGktn3OeW

They seem decent. 6 GB RAM, 128GB storage and I have a micro SD to expand. It also comes with a pen, keyboard, and mouse. They don't seem to have any branding though, just "Android Tablet". Additionally returns aren't accepted.

Buying this would be significantly cheaper than a laptop + tablet + pen, but I don't wanna buy non-refundable junk. I'd be using this for university, math degree. I'll also note that I have a decent PC at home, so I'm not too concerned about whether it can be a powerful laptop or not. I mainly just need it for note taking & pdf viewing. Maybe some pictures.