Thinkpad X61's power adapter plus an eBay adapter takes much longer to charge X270

Q1:
I have an original Lenovo power adapter 65W 20V that was used for my X61 Thinkpad
& the adapter connects to the X61's round-shape power input: think the X270's USB-C
wattage is 45W & 19-20V only : correct me if I'm mistaken?

Q2:
I have an office-provided X270 Thinkpad that I bring home but to minimize the weight,
I don't bring home (to reduce the weight that I carry) its power cord & adapter that
connects to a rectangular shape power input : is this called USB-C?

Q3:
https://www.ebay.com/itm/Power-Converter-Cable-Adapter-For-Lenovo-ThinkPad-X1-Carbon-0B47046-Laptop-New/312038683433?_trkparms=aid%3D555017%26algo%3DPL.CASSINI%26ao%3D1%26asc%3D54339%26meid%3D36be1d55f6e34935bbc83593add17c79%26pid%3D101006%26rk%3D1%26rkt%3D1%26%26itm%3D312038683433&_trksid=p2045573.c101006.m3226

When I'm at home, I use an adapter to connect the X61's power adapter that I got
from eBay link above to power my X270 but this takes about double the amount of
time to charge up the flat battery of the X270 compared to the adapter that comes
with X270: is this due to the eBay adapter or the X61 adapter?

Q4:
If it's due to the eBay adapter, can recommend a good one to enable faster charging?
I try not to get an original X270 power adapter & place at home as it may costs up to
US$25