Texas Instruments SRE offer

I'm an MCA student from a tier-1 college, graduating in 2025. I recently secured a six-month internship at Texas Instruments (TI) with a 95% chance of getting a pre-placement offer (PPO). I've solved over 1,000 problems on LeetCode and have a rating of 1950+. While I always aspired to begin my career in an SDE role, the current market situation is challenging, with only a few companies visiting our campus this year. I'm extremely grateful to have an offer, and I have solid projects in the MERN stack. However, since there's heavy competition in this area, I decided to start learning iOS development to diversify my skill set and increase my chances of landing an off-campus SDE role at startups like Swiggy, Cred, and Grab. What would be the best way to approach these companies? Any advice on how I can secure an off-campus SDE role(I already to many companies with the resume having ATS score above 80 with or without referrals tailored resume according to JD but haven't got any response)?