My phone won't charge sometimes.

It's the 2017 model, not the OG K10.

I've had this phone for around 8-9 months now and it's been serving me perfect. I don't do stupid things with it and do my best to keep it running nice. A month or so ago when I put it to charge one night and woke up the next morning it didn't charge a singe %. The charging symbol was there but the battery wouldn't charge. The charger wasn't even heating up. I unplugged it and plugged it in again and it started to charge just normaly. Okay, I let this pass and soon forget about it. Sometime later I would put my phone to charge but it wouldn't even accept the charge source, it wasn't charging. No icon, no nothing. I tried re-plugging it a few times and still nothing. I plug it in one last time and wait for a minute or two and it started charging normally. I know that the cable isn't broken because I only charge my phone when I go to sleep and don't use it when it's charging. The battery holds up pretty well but I started noticing something strange too. When it's fully charged it would take a while for it to drop from 100% to 99% and so on until around 90%. Then when it hits around 50%-40% it would start draining fast. Every 10 seconds I would lose a percent of my battery. Sometimes it would just normally discarge without this issue. I didn't have issues for around 2 weeks and today it happened again with the charger not being accepted. Anyone got any ideas?