Usually after 70% battery, many phones will not 'charge rapidly' which is usually > 1amp. It should still say 'charging', which is 1amp. There are times where over 70% it will 'charge rapidly' and that's often when the battery internals are still cool/safe enough to continue doing so.
As for charging in general, you do need decent cables and a decent charger. With USB-C chargers buy original OEM or Anker/Aukey. Avoid any other cheap ones for your own good. Avoid ones that don't have a UL rating (or the European equivalent) on it. Decent cables have become easier to find the past year. Again the Anker/Aukey/Amazon Basics are great off Amazon, so is Monoprice and even Best Buy's Dynex. Actually I recommend the Dynex version of Apple's lightning cables, but that's off topic.