Why Tc and EPW strength is reduced using SOC

Dear all,

Could somebody provide physical insight on effect of SOC on Tc and EPW strength? Why Tc is reduced after including SOC as shown in the paper?
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.99.104520
There are other papers too. It would be really helpful if somebody can explain.

Sincerely,
Shubham