failing to print not matched lines from second file

[tester_V]

Greetings!
For some reason, I do not get the iterations in Python.
Especially with "Else".
here is a problem, I have two files, File-1 and File-2. I must use File-1 lines to find lines in File-2.
I have no problem finding lines but I cannot print Lines that do not match (from File-2)

File-1 lines:
03/28/2021,P,6,LINE2
03/28/2021,P,9,LINE4

File-2 lines:
03/28/2021,P,16,LINE1
03/28/2021,P,6,LINE2
03/28/2021,P,9,LINE3
03/28/2021,P,9,LINE4
03/28/2021,P,8,LINE5
03/28/2021,S,95,LINE6
03/28/2021,S,1,LINE7
03/28/2021,P,46,LINE8

I need to print out only lines that do not match:
03/28/2021,P,16,LINE1
03/28/2021,P,9,LINE3
03/28/2021,P,8,LINE5
03/28/2021,S,95,LINE6
03/28/2021,S,1,LINE7
03/28/2021,P,46,LINE8

But the code I wrote prints this:
ELSE -->> 03/28/2021,P,16,LINE1
ELSE -->> 03/28/2021,P,9,LINE3
ELSE -->> 03/28/2021,P,9,LINE4
ELSE -->> 03/28/2021,P,8,LINE5
ELSE -->> 03/28/2021,S,95,LINE6
ELSE -->> 03/28/2021,S,1,LINE7
ELSE -->> 03/28/2021,P,46,LINE8
ELSE -->> 03/28/2021,P,16,LINE1
ELSE -->> 03/28/2021,P,6,LINE2
ELSE -->> 03/28/2021,P,9,LINE3
ELSE -->> 03/28/2021,P,8,LINE5
ELSE -->> 03/28/2021,S,95,LINE6
ELSE -->> 03/28/2021,S,1,LINE7
ELSE -->> 03/28/2021,P,46,LINE8

I have to split lines in File-1 and File-2, some additional processing required in the lines.
Here is the code:

with open (file_2,'r') as l_few :
    f2=l_few.readlines() 
with open (file_1,'r') as f1:          
    for lf1 in f1:
        lf1=lf1.strip()
        sp1 = lf1.split(",")
        for lf2 in f2 :
            lf2=lf2.strip()
            if lf2 :
                if sp1[3] in lf2 : 
                    spL2=lf2.split(",")
                    #print (" File 2 Line matched --> "+lf2)
                    #break
                else :
                    print (" ELSE -->> "+lf2)
                    #break

Any help appreciated, I exhausted my resources, trying to solve it for the last 3 days.
I tried to move "else" all over the place and used "break" but still cannot make a clean print of only the 'Not Matched' lines.
Thank you.