You won’t get 300 miles from a full charge of the 64kWh Kona unless you’re doing a very low speed with no braking. Expect 200 to 240 miles of normal driving, less perhaps in winter.
So, you’ll be needing an occasional boost at a Rapid charger & they range in cost per kWh between free and 69p/kWh (you can knock this down to 58p/kWh easily enough).
As for where you put a charger, there are always alternative options, if you are considering putting extra chargers at workplaces/relatives across the country then the humble 32A commando socket and carry a smart charger with you although most people will have a domestic electricity tariff of around 15p/kWh so stopping at a Polar 50kW Rapid charger would work out at much the same & be quicker as long as they are on your journeys.
Check your journeys on Zap-Map to see if your routes have the correct chargers (50kW, 150kW, 350kW CCS chargers). Check Zap-Map to see if your destinations have the correct chargers (7kW, Possibly 32A Commando although most are at companies & not open to the public).
Doing a lot of research before getting an EV will mean you have some idea of what to expect & what you need to do to avoid getting stranded (Plan A, B, C, D for every journey).
When it comes to charging at home overnight, bear in mind that some tariffs have a low rate for a number of hours, say 5p/kWh for 4 hours. If you need more than 4 hours (that’s about 100 miles worth) every night then you need a longer low rate, say one at 8p/kWh for 7 hours, etc. Or possibly go “Agile” and accept that 10p/kWh some nights can be normal & 0p/kWh is an occasional bonus.
Fitting an EV into your life is a major change and needs lots of research, there are a few of us now who have made the changes on this forum, all of us with differing circumstances, EVs, and solutions, but none of us are looking at swapping back to fossils.