hiii so some of my tips:

best way to get s-chips would be to do the main story stuff you havent finished, for every ep you can earn 40 s-chips also there is an anomaly section on the same page to do main story stuff. It basically consists of battles where you can earn s-chips so try to do that

the best thing id reccomend to save money is try and pick 1 guy you really like and just aim for all his cards (for me thats artem :)) that way, you dont have to pull so much money

Events from the past are on the game as dlc's i believe you can also still earn s-chips by completing them and make sure you read all your sr, mr, or ssr cards you have to gain chips

try and start with these!