There is an underlying truth that no one ever talks about because its uncomfortable and not what we're supposed to say in society, but it is nonetheless true. No one outside of your home really cares about your career that much. People will make the right noises but they're really not that interested. Careers are fleeting and have very little impact on the lives of those around you.
Inside your home, your partner will be supportive and happy for you because on a basic level it will bring in extra income or benefits and it makes you happy which makes them happy, but to your parents it doesn't actually mean much outside of a few supportive remarks. It doesn't change their lives in anyway.
In contrast, a grandchild will be a huge addition to their lives. They may have held a long standing desire to be grandparents and its now happening.
The two things aren't comparable in their eyes, not deep down.
I had a high flying successful career with academic achievements and travelled to exotic and interesting places until my late 30s. It wasn't until I had kids that I noticed the shift in superficial platitudes of 'well done' and 'you're doing so well' every time i got a promotion or achievement to actual deep interest and engagement when I had kids. It felt frustrating as I'd worked so hard but it was the reality of the situation.
Try to separate the two things out. It's not a competition between you and your sister for your parents attention. If you continue in that mindset it will make you unhappy.
Enjoy your career and the affirmation from those in your professional circle. You sound like you have a supportive partner, which is great.
Be proud of yourself for what you've worked hard for and happy that you've made choices to walk your own path. Also, cut your parents some slack, they're probably just very excited and joyful about being grandparents.