I Am Invincible and There Is No End to My Learning

Serious version: My original dream has been realized, my strength has reached its limit, and my desires have been wiped out by time. Where should I go... Until that day... Funny version: time travel! There is a system! Invincible! What to do now? I don't know what to do anymore. I can only learn new knowledge and upgrade to maintain my life. Tentative world: About the time I traveled to another world and became a slime → This brave man is obviously super strong but too cautious → Inhuman / There is a beast / 1031 Halloween Street → The Valkyrie at the end → Oriental Fantasyland → Undecided... This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.