First line with digits before last line

[tester_V]

Greetings!
I’m parsing log files, 95% of the files have the lines I’m looking for.
5% does not, and I must get the first line (Line starts with date time “2022-08-14 14:37:46 ”)
And the last line (Line starts with date time “2022-08-14 14:39:00”)
The problem is not all last lines have a Date Time in the string.
I need to read the lines before the last line until I find one that starts with the data time ...

Here is what I got so far, it does not work as I wanted :

import re

with open(r"C:/01/last_line.txt") as mfiler:
    frt_ln = mfiler.readline()
    print(f" Fl -> {frt_ln}")
    
    for rn_l in mfiler: 
        if 'Start' in rn_l :
            continue        
            # do something with the lines
        last_line = rn_l
    print(f" Last Line ->{last_line}")
    if not re.search('^\d+', last_line) :
        next
    else :
        print(f" Line with the DateTime -> {last_line}")
        #break

Here is a short example of the file:

2022-08-14 14:37:46.523,17784 ,Information,"==================== Bac Start Run ===================="
2022-08-14 14:37:46.523,17784 ,Information,"Bac Info:
[DS_DK] Bac Test Result : Passed
[DS_DK] Bac Iteration Result : Passed
2022-08-14 14:37:46.524,17784 ,Warning
Condition: NO Condition
Allowed Stages: Any Stage
Set Type: Hard
2022-08-14 14:39:00.032,15060 ,Information, Available network interfaces :
[Bac Setup] Ethernet Connection -2
[Bac Setup] USB 3.0 to GB Ethernet

Could you help me with this?
Thank you.