That is so totally not a string.format issue that it is not funny.
Please consider doing a little basic debugging yourself.
Values (abc,efd,gr,y,t,ui,u,re,re
This is not valid SQL. See, string values have to be in paranthesis of some sort (‘abc’ instad of abc).
Simply speaking your (btw, the old string.format syntax is hard to read – learn to use $”” strings, the new syntax for formatting in .NET 6.0) generated SQL is bad and you never considered this a SQL error.
Now, for the length issue – that is no, there is no sensible limit that you would reach. There is one, but it is LONG (not sure about the string limit – 2 gigabytes RAM?). It is likely you have a serious presentation issue (as in: The string is there, you just do not see it, like in the debugger, which may limit the output length).
I would reformat that to use he new $”{paramname}” syntax – it is a LOT easier to debug once you hit 10 or 20 parameters.
Please also note: The ToString calls on all those parameters are surplus (default call anyway).
solved Length of string in String.Format()