everyday i see people constantly complain that they cant find a boss or just dont want to grind out islands just because they are lazy.
but incase you cant find what you need:
https://valheim-map.world

after 21 in-game hours i used this finder to locate moder and some leviathan serpents. just type your server seed in and it will locate your bosses and other things. i wouldnt reccomend this for newer players because the most fun parts of the game is to find, explore and inhabit new islands. but if you think its taking too long ^^^^^^