Joycig is not the popular brand Joye who makes 510. It is Joy which is not a 510. I have special hate for Joycig because their name is deceptive for people looking for Joye 510.
I have no idea what model Joy is - the atty could be RN4081, Joye 306, Trio or other.
And you don't need prefilled carts - BUY
eliquid - there is some way to refill everything. With 3-piece ecigs that have carts that fit over the atty - Take a cart off the atty, stick a small unbent paper clip in the mouth hole, and push up the
juice cup. Add juice. if the stuffing is recessed, use the paper clip to reposition it near the top. Push the juice cup back down by its edge. When the stuffing gets old and cranky, cut blue foam stuffing for the cart. I am still using the first cart of a super-mini I bought 4 months ago.
A lot of rebranders have supply problems. Unfortunately, that is one more reason to buy an ecig that is a known well-supported model that multiple vendors carry supplies and parts for. And FYI the rebranders did not invent anything. They are selling Chinese models they bought in bulk for $11, but if you don't know what model it is and whether anyone else carries stuff for it, then you are stuck with the one vendor, as they intend.
Re attys - I have a little M402/M401 manual and I keep the attys clean and never let them get overheated and I am still using my original attys. If the atty is getting too hot then it is not getting enough juice (check stuffing position, add juice) or the atty is dirty and clogged and you may be overheating it trying to get vapor. It's not my main ecig anymore but it kept me off cigs for the first month and I bought some slightly more powerful and supported ones - 510 w/ standard and mega xl batteries (all manual) and a Vapor4Life KR808D-1 standard manual. They are enough for me. Some need or want to go one step higher in performance to fat battery models to Ego and Riva 510, or for KR8 the Elegant Easy or Pigcig
Perhaps the "Joy" is not a powerful enough ecig for you. Super-minis will only satisfy an ultralights or lights smoker who doesn't need big drags or much TH and is willing to screw with tiny carts adding juice. I used a super-mini for my first month.