Side gig you could setup a LLC run it properly even without E&O and within reason if you do get sued the worst case is a judgement against the LLC. You will still be protected and only direct assets of the LLC would be at risk. Bankrupt it, close it and move on. Not advocating this way but this is how a lot of home contractors operate.
Assuming you carry E&O, would you mind telling me who you buy it from?
Generally depending on limits you are probably somewhere between $500/yr to $1500/yr. of course higher limits or high risk areas change those drastically.
There is an online company. I think called something like tech insurance and they write policies for most top end providers and get how to help freelancers and small consulting shops. I used them a couple of times in the past.
Also look into an umbrella policy personally too. There are some differences but it may make sense depending on your situation.