Retirement tax questions

Yes ... read the 941 & the 941 instructions (posted earlier)... EACH employer will withhold 6.2 from the employee + 6.2 for the employer match until that employee has reached that year's maximum amount.  At that time the SS withholding & employer portion stops for that employee for the rest of the year.  

Your business did not pay you the max in SS wages so the employer is required to continue to withhold and pay until you hit that max with them ... your having another employer is immaterial to this calculation.  I see where you think this is unfair because it is unfair however that is how the rules were written.   

Now if your business withheld/paid in too much because your business failed to recognize the limit and actually paid in an excess then and only then can you amend the 941 to get the excess paid in for the employer but you did not indicate that your business paid you more than $142,800 in wages in 2021 or $147,000 in 2022 but if they did then by all means amend the 941.  However if the limit was exceeded by the combination of more than one employer you have no basis to amend.