I'll update the LB post soon but if you're buying a charger I'd say I recommend getting a 0-15v 500w 'adjustable charger' ( I tried copying the AliExpress link but for some reason it won't) which can be used to balance the cells. The one I got is sort of like a blue loaf of bread shape.
The batteries naturally balance over time but you can speed things up a bit connecting them in parallel and charge at 3.65v so they're all the same.
How?.
When you get the cells connect them in parallel, (connect all the ++++ and all the --- together). Then attach adjustable charger that is set to 3.6v and charge.
Once done disconnect and reconnect in series so your voltage now is 3.6x4 (14.4v) and all cells are the same. You can then, if you need to, charge at 14.4 v using same charger) and 35amps or whatever you can max it to.
That's balancing.
Can also use the same charger for lead acid but whatever you do keep the amps down low, maybe 3 or so, it's not like lithium that'll take anything you can throw at it.
You can do it (rebalance the battery) each winter when you put your battery indoors (they hate cold/freezing temperatures so keep it happy indoors) so it'll be in top shape come spring.
I just saw a post about temperature and susceptibility to explode. No. The BMS has temp control and the DC to DC charger also has temp control.
If the battery is defective then it might fail but that's the same for anything. Under normal circumstances they are safer, no liquid (unlike lead acid) and cold.
I've made mistakes with these batteries, I shorted 2 out by mistake which killed them and they swelled up but no 'explosions'
I understand the waryness of new technology but get hands on with it you'll realise it's really good and safe.