Wow, coming back after 3 years must be like going back to high school. A LOT HAS CHANGED! Champions is one of the best and most significant changes since you’ve been gone. When a character is at max level, you can pay ISO to “champion” them and then add more levels as you get their covers. Champion rewards are very good and it makes it worthwhile to roster and champion everyone. I’m not joking, everyone! (except Bagman, Devil Dino and Howard the Duck). Champion rewards give you covers of the next tier, or ISO or HP or CP or tokens. So, you can progress faster with champion rewards, but the downside is paying a fortune for roster slots and another fortune of ISO to max/champion them, but…it pays off in the end. it’s a long term strategy, building up over time.
Another big change is player ranks and SHIELD clearance levels (SCL). This is meant to separate everyone into tiers of similar strength players. It kinda works. But the good news is that every time you gain a rank, you get a ton of ISO. It takes XP to gain in rank and that XP comes from adding covers to existing characters, which includes champ levels. So, that’s another reason to roster everyone. Some people even have 1* farms where they constantly max cover 1*s to gain XP, then sell them and start over. This is beneficial up to a certain rank, instead of just selling the cover right away.
VIP membership, Bonus Rewards and Bonus Heroes are also new to you. They’re just ways of getting extra rewards. Command Points (CP) may also be new to you. CP is great because you can buy legendary tokens with them. The token stores and vaults are more elaborate than ever. Supports are very new, but so far, everyone thinks they’re useless.
In general, the game rewards players who have rostered everyone, because it turns into more rewards or at least a combat advantage with certain events or nodes. In short, rostering 4s is your bridge to 5 characters. Level 420 OML and Jean isn’t going to scare away people like it used to. Unfortunately, 5* PVP play is currently broken with 5Gambit being too powerful. Since you currently can’t compete in PVP and you would lose out on PVP rewards for a very long time until you can compete, I would sell your OML and JG and scale back to the 4characters.
So, here’s my advice: accept that you’re in a bad situation and the best way forward is to focus on the 4* tier until you can max/champion a 5* fighting team, which will take a long time. So, sell OML and JG and build up all 4s. 2s and 3s are not useless either. They can provide champ rewards to fuel your overall goals, plus it’s good to have them strong for required nodes/events. The real point here is to enjoy the game and 4 land has far more variety, plus I find it more fun to get champ rewards than to just sell the cover for some minimal ISO.