dealers/market makers are legally limited in their balance sheet there are ratios that they must respect, or face legal consequences (e.g. fines) check Basel III & Leverage Ratios for more info - I also wrote about it in my past posts committee recommendations develop into law
in a monthly maturity/tenor timescale - the repo funding rate has very direct effects this makes sense - if your bond is maturing in ≈1 month, every day is significant so you see more immediate effects from federal reserve's SRF operations / repo funding fee increases