It's not that you CAN'T have a good relationship with your mom if you have a scorpio moon, just that it's less likely in and of itself. But there are a lot of variables to take into consideration. Like aspects to your moon from the rest of your chart, whether they're gentle or challenging, and how your mom's planets connect with your chart. Both Pisces and Capricorn are harmonious with Scorpio so you have that going for you.

My friend has a Scorpio moon and her relationship with her mom has always been a bit strained. Her mom definintely made parenting mistakes including being too controlling, and my friend remembers all those mistakes and repeatedly throws them back in her mom's face decades later in true Scorpio fashion lol. But her mom went to therapy and my friend had a baby of her own and moved back into her mom's house for a while, they both got more mellow and their relationship has been repaired a lot. So it's not like if you have a Scorpio moon your relationship with your mother is doomed forever, just that it can potentially be more challenging depending on other stuff in your chart.