Well how I do it is by asking friends who are already working in these companies. The #1 most useful thing I did in Uni was to keep in touch with many of my batchmates who were interested in joining banks as SWE.
From there I just see what their experiences are like. For example I have 3 friends in JPM, pay is 5.8 - 6.2k, two of them have shitty WLB, they work till 8pm on most days except Fridays while that 1 other friend only does 8 to 5pm everyday.
I got some batchmates in
OCBC tech team, lower pay, better WLB.
Then I basically rank these banks based on what I want. ( Better WLB vs better pay )
That's how I do it tbh. Glassdoor reviews imo are useless... I'm currently in a large tech company with >4.0 glassdoor rating over 30k+ reviews, almost 0 negative reviews yet everyday I see employees arguing in standup meetings and devs fighting over on-call rotations lol.
You really need to get close to your uni batch mates and keep them in touch to get all the useful info.