I am an individual (i.e. not an organisation) with a hobby website that has no commercial interest, no third party affiliations, no social media links, and no third party analytics.
When a user opens the site, their visit is logged. I track timestamp, IP, and some information I obtain using that IP - city, region, country, and internet service provider. A cookie is given to the user with a unique identifier to assist in some deduplication of visits. I do not keep this information secure, in fact the explicit purpose of the site is as a public "guest book". The site publicly displays all of the above information of all past visits in a large table for anyone to see.
I have seen this question, which asks whether web applications as hobby projects need to comply with the GDPR, however I feel that the way I am treating data here is somewhat unique, especially as it relates to third parties.
Do I need to comply with GDPR? If so, how? Is it enough to obtain consent before adding people to the guest book, or do I need to do anything extra about the fact that the information is insecure?