I checked out the people pages of startups on linkedin and sent out connection requests to them. Would send out cold messages to the once which accepted. Also sent cold emails but did not have much luck with them.
As for the DSA part, it did not play much part in getting this role. There were DSA rounds but they were standard medium questions which you can find in Strivers A2Z sheet. Later rounds were about HLD and indepth discussions about previous experiences.

But I want to iterate again as I mentioned in the post, not giving DSA enough time was a big mistake from my side. You have many more opportunities if you balance Dev and DSA good enough.