Hey.
With the detail you provided, I don't know how or if your situation relates to mine, but I'm estranged from my parents too. I don't really relate to them beyond as these people who were important figures in my earlier life... the sometimes-reluctant providers of room and board who tried and often failed to do well at parenting. In this case, that took the form of various kinds of physical and mental abuse, along with general emotional unavailability and absence. Naturally, our relationship was burned pretty badly.
I say all this because I also really only see them during holidays or get-togethers with other family members. I used to want to wait it out until they "got better", so I could trust them, let my guard down with them, or otherwise get close to them in ways I wished I could have when younger. But there's a point when you get burned too many times... when you've spent so much time trying to build a better kind of interaction with them while their old ways are so slow to change that it's time to change your approach instead. Hence, these days I try my best to represent who I am and what's important to me, while also keeping my emotional distance, letting them know when I disagree or can't do something, leaving or refusing to talk with them sometimes, or whatever else my day-to-day functionality needs to keep going, without excusing their behavior or our history.
Even so, this leaves a lot of unresolved baggage between us. Often when we're together, I bite my tongue and withdraw from them, rather than opening the old Pandora's Box and letting all the things that happened between us over the years explode out all at once. I try to talk things out with them gradually over the long-term, without ever getting overly committed to "making things between us better," because ultimately I can't do that on my own, no matter how hard I try. It requires dissociation too; meaning putting your feelings into a mental box and forgetting about them for the time being, while hopefully remembering to deal with them at some point in the future. There's times when the degree of dissociation being around them requires has lead to listlessness and depression, and feelings of being drained or emotionally exhausted. Worse, sometimes I completely lose sight of the things I should be feeling and talking with them about afterward, so this drained and emotionally-dead feeling persists for weeks or months. I've found that talking to other people about them from time to time helps too, so I don't forget it, but can also take my time mentally and emotionally preparing myself to deal with.
Again, I don't know the details of your situation. And given that, the only real advice I could provide is that talking to us about the situation here might help you better understand the situation, define it better in your mind, and enable you to deal with it. Relationships like these can be really complex, and I don't know if there's ever a "best" policy for how to proceed. At least not that I'm aware of. But maybe my experience gives you a better framework to compare your own experience against?