Password protect your services, set up your web server correctly, use cloudflare for some extra security against stuff like DDoS/DoS attacks. Also less is more, do not expose what you don't need to expose.
There is always inherent risk with opening up your stuff to the world wide web.
Some stuff you can't even secure yourself; some services just have bad security practices. The only way to fix them would be to wait for an update or submit a pull request.
I loved the new Reddit UI, I should not have to click images to enlarge them. Really hope Lemmy gets something similar.