Advice for altering my behavior in my relationship with my girlfriend of four years. What short-term strategies can I implement?

Hello! I've been in a relationship with my girlfriend for nearly five years, and we've been discussing marriage. However, we've been facing a recurring issue lately. She's currently going through a tough time after losing her job. She's also trying to complete her studies at a later stage in life to create better opportunities for herself. Additionally, she's undergoing therapy for past traumas and dealing with some personal challenges stemming from an unstable family situation with minimal support. As a result, she experiences a lot of stress and anxiety, but I admire her for making significant progress through her therapy and personal efforts. In contrast, I have received a lot of family support, finished my studies, and found a stable job. While I may come across as somewhat of a "mama's boy," I've struggled with social anxiety and shyness. I do my best to help her and lighten her load at home; I often cook, and we share cleaning responsibilities while looking out for one another. Generally, our relationship is strong, and we share similar interests, but therein lies the challenge. The stress she’s under and our very close relationship with my family (with whom we both maintain daily contact despite living far away) can sometimes create tension. Occasionally, she has emotional outbursts, leading to heated discussions. These tend to follow a pattern: she gets upset about something I've done, I think her reaction is exaggerated, and then I find myself at fault. Afterwards, she elaborates on all the small things I've overlooked throughout the week and how I failed to recognize her signs when she was having a bad day. I want to change this dynamic. I aim to manage the small things I do throughout the week better, reduce her stress, and address any issues before they escalate. I want to be a supportive partner for her. We've discussed therapy, but adding another session is overwhelming for her considering her current therapy and group work. Therefore, I plan to seek therapy for myself to improve my communication skills and better support her. However, I'm looking for immediate strategies to enhance our situation in the short term. Do you have any suggestions based on similar experiences or advice on how I can navigate these challenges? Any book recommendations would also be appreciated!