Your w/kg doesn’t need to improve for you to get faster though. Greater total power at the same w/kg will mean you’re faster.
Every GC rider is training at the gym now. Strength training is integral to any successful cyclists programme (especially in the off season).
I’m really not trying to do you down, but your weight is so far below the normal range for someone of your height, that I truly believe that a gain of 10kg would result in greater speed, power and durability on the bike. Look at Jonas Abrahamsen, as an example of a rider who gained a lot of weight intentionally, and found greater success with it.
I’d point out also that Pogacar is 1.78m and 66kg. He isn’t exactly heavy-set in his physique and there isn’t anyone that climbs faster than him or does higher w/kg.
As a final point aside, I would also encourage you to think of an additional benefit of higher bodyweight as greater resilience in times of severe illness. Around 20 years ago, one of my wife’s best friends (who had always been remarkably thin) was taken ill with severe colitis, which ultimately resulted in her having her large intestine removed. She came very close to death (in her mid-twenties) and having minimal body mass meant she had nothing at all to fall back on.
Either way, as much as I absolutely love cycling, I do think that the single-minded pursuit of w/kg isn’t necessarily healthy or indeed productive for going faster on a bike.
