I discovered that three independent variables have standardized multiple coefficients (SMC) equal to 1.02 on a dependent variable. Are there any approaches to be considered for modifying a high R2 in a regression?
Do you mean that each independent variable has the same value of 1.02 or the general multiple linear regression model has this beta value. In regression check both predictive R squared value and Adjusted R squared value especially when there are many predictor variables.
Check for your residual plots, without seen the residual plots it is hard to recommend a way to better fit your data to the model