Look at some positives. You’ve been working in the field for a few years so you can clearly do the job. You’re applying during a pandemic and the market is tough right now. You’re clearly interested in tech or you probably wouldn’t be hanging around on HN on a Sunday, and this in my mind already puts you above many others!
So what can you do? Apply for jobs that don’t require algorithmic/systems interview tests. They do exist, I’ve worked for a couple! Or, game the system by studying interview questions (Crack the coding interview, competitive programming sites) so you’re more prepared. Of course you could also look for another job in a different industry, but I don’t think you really want to and are just a bit anxious with interviews. Finally, consider moving into SDET. A background as a developer makes the transition quick, you’re immediately competitive compared to those without dev backgrounds, and salaries are similar. They don’t tend to have the same interview questions.