Feeling like our baby is not as important to my partners family as our niece

Feeling really torn- we love my partners parents and his sister and our niece who live with them but we’re avoiding taking baby girl into their house as its a complete mess, not clean and has three poorly controlled dogs- before we had baby was just not particularly pleasant but doable but now we really don’t feel comfortable with our newborn being put in this environment for her safety and ease of trying to bf, change and let her nap etc its just not enjoyable. Its been fine so far as we’ve met else where although it does feel harder to have any quality time without spending money but now the subject of Christmas has come up and I’ve said we will happily host as its much easier and avoids their house but my partners sister has said flat out shes not taking our niece away from her toys just after shes opens them but because they live with my partners parents and she has no other family to go to it we either have to go there or we cant have Christmas with them. It feels like we’re always the ones to have to work around everything when they make no effort to. I understand where she is coming from but we also spoil our niece (4) with presents and I feel she would adore being at ours for Christmas (where it is tidy enough for her to play! And we can all eat together without being surrounded by rubbish on the table and not being able to move for the crap that is left untidied and dogs jumping up at you constantly) as she adores being with us as we do her but I feel so disappointed that we’re instantly pushed aside and that our daughter’s first Christmas isn’t being made to feel special too and because we dont live with them that she’s not as valued or prioritised by her grandparents and I worry about her future relationship with them because of this especially as the girls birthdays are only a week apart and despite a 4 year age gap my partners sister and mum are already trying to make joint birthday ideas (our daughter is barely 2months!!) and which are all only suitable for our nieces age!-basically getting us to split the cost of the party! I feel like having Christmas just the three of us will just be like any other day of maternity leave for me and I don’t want that and I love Christmas its made me feel really sad about it all and for the future. Sorry for the huge rant just feel so lost as what to do and getting so down about it-hormones probably aren’t helping!