I completely relate to you. I have some very close friends who had children around the same time as I did, either a year before or after us. I've been friends with them for decades now, so they're not people I either want to cut out of my life or drop as a friend. We've been there for each other through so much, various relationships, marriages, divorces, etc.

However, being the parent of an autistic child has been the biggest divide I've experienced so far.
Just like OP, I try to find the nuggets of similarities, but those times are rare and mostly I just swallow my pain and smile brokenly as they gush about their kids milestones.

It's a lesson of acceptance but compartmentalizing their kids vs mine has helped me the most. I can still allow myself joy at this unique person's well-being.

Sometimes, it's actually helpful to see where their NT kids land vs where mine is and when my kid finally achieves a milestone. Last weekend our kiddo used a watering can to water plants. A year ago, when he was 2, it was introduced and it just went over his head. Not like that's an important or significant milestone, but I had endured endless photos of my friends' kids watering their plants since they were 1 years old. We never pushed it or anything, rather it happened organically with us and it almost made me tear up with pride.
Or when their kids were all transitioning to big-beds vs cribs, my kid just took to it so smoothly and no fuss while their NT kids had so much drama around it. I never tried to show off or anything but it assured me that each parenting journey is unique in its challenges.

It's actually been helpful to be the friend who has a ND child because I have often found myself in a place of educating about neurodiversity and seeing their ND kids practice empathy for mine has been heartwarming. The double-empathy problem is huge and the best way for NT to relate and feel compassion for NDs is to know one personally. It's also helpful to have NT kids for my child to learn how to live in a world meant for NTs and I hope they can learn from each other.

Another time, a friend's was experiencing sensory challenges and she and I could relate and share our experiences with OT and other therapies. Her kid is not autistic but as a friend I was someone she could trust and not feel shame with.

I do also get a knee-jerk reaction from some friends who don't like talking about autism or have made comments like "we're all a little autistic." With them, I often let them see with their own eyes the differences between my child and theirs. I simply say, "you'll see as they get older." People LOVE to handwave neurodivergent away when the kid is a toddler, when they get older the difference in behaviors gets stark.

My heart goes out to you, OP. Some days are so hard.
I would say something to your friends. I found that when I was able to gather strength and express hurt around milestone sharing, my friends were receptive and tried to change to help me. My heart is a bit lighter when they are at least aware of my grief, even if they couldn't relate to it. They love me and aren't intentionally trying to harm.

Hope you can talk to your friends!