LastPass had a major breach in 2022 where attackers exfiltrated encrypted vault data. If you used a weak master password, those vaults are likely already cracked. LastPass also changed their free tier to limit you to one device type. There is no compelling reason to stay.
Bitwarden is open-source, independently audited, free for individuals, and has a better security architecture than LastPass. The self-hosted option (if you're into that) is excellent. The cloud version is fine and stores everything encrypted where even Bitwarden can't read it.
Export from LastPass: go to LastPass.com → Advanced Options → Export → LastPass CSV. This downloads a CSV of all your passwords.
Import to Bitwarden: create a free account at bitwarden.com, go to Tools → Import Data, select LastPass (csv) as the format, and upload the file. Every password, secure note, and address comes over perfectly.
Install the Bitwarden browser extension and mobile app. On the desktop, the autofill works identically to LastPass. On mobile, enable Bitwarden as the autofill provider in your device settings and disable LastPass.
After confirming everything imported correctly, delete the CSV file (it contains all your passwords in plain text), delete your LastPass account, and remove the LastPass extension. You're done. The whole process takes about 10 minutes and you'll never look back.