Hard time at slayer tasks

Hi, I am currently trying to level up slayer as I need it to progress quests. It’s currently at 35 and my combat level is ~75. Because of that, I chose Chaeldar for tasks. My current task is to kill fire giants and I just feel I am not strong enough.

Is there anything cheapish I can improve with my gear? Or should I do something else for leveling? I have to replenish food quite often so it took me quite a while to get the first 20 kills with 3k xp/h (…).

I already got a blessing which isn’t on the screen, rings seem too expensive as I only have around 500k left.