There is a lot of focus on your Sun sign in astrology, and this is because your Sun is who you really are, your true self. That makes your Sun sign very important! But, some people don't feel like their Sun sign much, or at all. What can show that being the case?
Let's review 5 options that can show you not feeling like your Sun sign (there are more, but we'll start with these):
First option: An abundance of other signs/elements
One way this may be present is if you have many planets in a different element from your Sun or in a stellium that doesn't involve your Sun. That element or the sign of the stellium can be much more dominant for you, and you may gravitate more toward that element or sign than the element or sign of your natal Sun.
Second option: A planet conjunct your Sun, Moon, Ascendant, or Midheaven
If you have another planet conjunct (aligned with) your natal Sun, Moon, Ascendant, or Midheaven, that planet can be a dominant force in your personality and life, maybe THE dominant force. This can especially be true when it's Saturn, Uranus, or Pluto. They totally overtake the Sun, Moon, Ascendant, and Midheaven, and can become the most important planet in your chart.
Third option: It's in your 12th house
The 12th house is the house of the hidden, so it hides energy. If your Sun sign is on the 12th house cusp, this may hide some of that energy from you. That's even more the case if your natal Sun is also in the 12th house. Completely hidden! The 12th house ties to the subconscious, so you may not be consciously aware of how it plays out in your life and personality. Gaining more of a connection to your subconscious can help with that. This can also be seen with the general planetary ruler for your Sun sign in the 12th house (like Mars if you're an Aries Sun, Venus if you're a Taurus Sun, etc.).
Fourth option: It's intercepted
Depending on which house system you use to create your natal chart, you can have intercepted signs, which are signs that don't appear on any house cusp and are fully contained in the house that falls in the previous sign. This can be most obvious when your natal Sun is intercepted, and you're cut off from the energy of it. But like with the 12th house, you can also see this with the planetary ruler of your Sun sign intercepted (so Saturn intercepted for a Capricorn Sun, Uranus intercepted for an Aquarius Sun, etc.).
Fifth option: The planetary ruler of your Sun sign is anaretic
The anaretic degree is 29 degrees of any sign, and in your natal chart, any planets at the anaretic degree can either be played up to the nth degree or are totally ignored - and it's usually the latter. If the natural planetary ruler of your Sun sign is anaretic, this can show you not connecting with your Sun sign (like an anaretic Pluto for a Scorpio Sun, an anaretic Neptune for a Pisces Sun, etc.). You need to work on bringing that energy out so it's not so unavailable to you, but also use it in a healthy way, not overdoing it.
Suggested Reading: Aspects Between the Natal Sun & Moon