I (24M) am unsure how to handle my girlfriend's (24F) ongoing emotional distance.

I'm not one to typically seek advice, but I'm feeling pretty conflicted and having trouble seeing the situation clearly. I'm a 24-year-old man and have been in a relationship with my girlfriend, who is also 24, for a year. Lately, I've sensed that something's off, especially since around November. We live apart—she has a roommate— and we usually see each other once or twice a week. Our outings typically involve watching movies, going for walks, or having dinner together. This has been our routine since the beginning of our relationship. I've always found it a bit odd, as my friends and I used to spend much more time together with previous partners. After coming out of a more intense relationship, I thought a change in pace would give me some much-needed personal time. I assumed that as our relationship progressed, she'd become more open. Unfortunately, that hasn't happened, and it's increasingly bothering me. I've talked to her about it, and she cites her exhaustion after work and an unpredictable schedule as reasons for her limited availability. While I understand where she's coming from, I also believe that being adults means we need to manage our time effectively in a relationship. There's nothing especially 'wrong' with her; she's not controlling or prone to starting arguments, which is why I've tried to overlook other issues that have made me uneasy. In the earlier stages of our relationship, we were intimate almost every time we saw each other. However, in the past few months, I can count the number of times we've been intimate on one hand. I’ve hesitated to bring this up, as I don’t want her to think that my only concern is the frequency of our intimate moments. During our last meeting, the atmosphere felt strained, almost like nails on a chalkboard. Conversations seemed forced; when I shared insights from a book I was reading, she just responded with a disinterested “oh.” Although I’ve always felt our interests were somewhat different, I believed we could bridge that gap. I genuinely try to engage with the things she enjoys, but that moment hurt. Additionally, I noticed that she didn't touch me at all, while she used to be more physically affectionate. What really unsettled me was that she had just gotten lip fillers the day before and gave me a quick peck, saying it was because her lips needed to heal and she wanted to avoid complications. But then, she proceeded to vape throughout the evening. I'm feeling lost on how to proceed, especially since my friends have given me a mix of conflicting advice. I'm seeking some impartial perspectives on my situation. Thanks for taking the time to read this!