I was wondering if I have to calculate my Load removed time myself or if I can just send the speedrun with RTA. If I do have to calculate it myself how do I do that, I've also seen people's timers pause when they go in a transition but idk how to do that

I believe there is an autosplitter which either works with the vanilla game OR has a specific mod paired with it. I am not 100% sure as I do not run Silksong but I've done attempts in HK so it may just be a livesplit autosplitter. For more help I HIGHLY suggest the discord. <3

The autosplitter (aka Load Remover) is just a part of Livesplit. If using the Load Remover, Livesplit must be clearly visible at all times. If that was not setup when you recorded your run then it will be timed RTA. There are setup guides that include sections for Livesplit and the autosplitter here and here. Joining the discord is highly recommended for any additional help.