Hello, I examine the Determinants of Banking Profitability. I have 3 Dependent variables that will be examined separately. I have Bank specific, industry-specific and macroeconomic variables.
Dependent are ratio numbers all the others are in percentages and I got 2 dummies of 0,1. My dataset is Panel I have N=118 and T=20. There are missing values in this dataset.However when i xtset the panel it says that it is strongly balanced.

I got in total 32-33 variables excluding Bankname, year and ID.

So I have started with normal regression and i did various tests. In particular, I got these results:

1)Heteroscedasticity present --> so I need robust

2)Omitted variables-->biased OLS -->fixed effects

3)Model specification through linktest-->not correctly specified

4)Multicollinearity-->present through CorrMatrix and VIF--->fixed

5) Normality-->not present through Shapiro Wilk

6)Breusch and Pagan Lagrangian multiplier test -->random

7)hausman---> FE

8) time effects through testparm-->needed

9) i cannot test cross-sectional dependence with pesaran nor xttest2

9)GroupWise heteroscedasticity--> present

9) autocorrelation through xtserial--> present

So my question 1) is which model should i run just xtreg y x1, fe vce(robust) or xtreg y x1 i.year i.id, fe vce(robust)

2) if anyone know how i can write the syntax for One step system GMM for my variables?