I have seen some other companies also doing the same thing and would suggest you not to panic as there are job openings coming up. Even I got a job recently after the company where I interned didn't convert my internship regardless of the fact that I worked a lot for them.
Here's what I can share from my experience:
Have a nice profile on LinkedIn, Naukri, Indeed, Wellfound and other job platforms. 6+ months of internship is great to have on resumes. Many HRs call by looking at your profile. Have atleast intermediate level projects on your resume, small projects aren't good enough. I am a MERN stack developer and I was able to apply 4-5 jobs daily on LinkedIn during weekdays, sometimes it use to go 10+.
You have time till December so you can plan which company is good to work at and go for cold emails/reach out to their HR. Normal posts looking for jobs are relatively less effective. And always try to get referral as there are thousands of people applying for same job. You can get shortlisted without referral too but chances are less. I wasn't getting shortlisted with just frontend projects so I learned fullstack and then I was able to get shortlisted regularly even without referrals. Manage both dev and DSA equally. Many companies will also give assignment as part of their hiring process while some can have DSA as first round.
Note: Don't fall for scams, do proper research for any companies that reaches to you and if a company asks for money during hiring process u can take it as a red flag.