koyu.space recommends you using strong passwords and two factor authentication which can be enabled in Preferences > Account > Two-factor Auth. If you use the same passwords across different websites you are at higher risk getting your account hacked from a data breach. Of course we will disable your login if we detect that your account might have been hacked and send you an e-mail on how to get your account back.
Since koyu.space is a relatively small instance there is not a big attack surface than on mastodon.social as this was actually happening. Hackers used breached password databases to get into some older inactive mastodon.social accounts. But still, do yourself a favour and care about your account security as we are limited in helping you.
That's actually all I wanted to say.