It's a striker fire.
Part of the heavy trigger pull is that you are also "loading" the striker for a good hit on the primer.
If you lighten the striker spring, you may experience light hits. You could also create other problems.
So look at the trigger return spring. Maybe that could be lightened.
Remember that springs lose their tension with use. Maybe some range and dry-fire time?
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Life Member NRA
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Former President of the ECPT (Eifel Combat Pistol Team)