Help understanding USB-C charging

I finally made the decision to bite the bullet and go to a new touchbar mac. I wasn't wanting a touchbar, but wanted a new 15" screen.

I have been doing some trial and error tests with charging this thing. I hate the dongle hell that I am going through with USB-C, but it seems to be worth the trade off by getting more flexible charging. I am off the grid quite a bit.

I have found some USB-C external batteries, but none that are 87 watts. I have an Anker Powercore II 20,000 and have found that it will charge my 15" MBP, but only if it is off (sleeping) at the time. I use a USB A to USB-C cable to achieve this. So I am asking for some help understanding how this all works.

1. Does it matter that I charge USB A to USB-C other than speed of charge? In other words, does USB-C to USB-C offer anything more than faster charging speeds?

2. Does it "hurt" my battery to charge very slowly off of a battery pack? Even if it takes all night I can get another charge the following day.

3. Do you lose anything in the USB A to USB-C conversion in terms of power? I'm thinking do I really need a USB-C port on the battery pack if the only downside is slower charging? If it doesn't damage the battery then I am fine with this.

4. I also have used a USB A iPad car charger to charge my laptop. Does this "hurt" the battery.

Thanks for the help. I'm perfectly happy just using a trial and error approach to figuring out what will work and what will not. I just don't want to ruin my new laptop only to have Apple tell me that anything other than an Apple branded charger shouldn't be used unless that is really true.