Ask HN: Should I shutdown my 20 year old SaaS sideline?

I have a 20 year old saas sideline in the UK which makes about $10k a year (very little work). It is a vulnerability nightmare. I'm in my 50s now and decided I don't have the energy or desire to rewrite the code. I've tried to do so over the last 6 months but never get anywhere. I work in a full time job. My head is a muddle. What questions should I be asking myself about whether to put it to bed or keep it going?

Ps. I'm a one man ltd company